This is the Fourth Chapter in the slow MtF transformation story, The Roommate. This is my first story, so constructive criticism is welcome and encouraged. Thanks to all who helped edit this chapter, and all who have given feedback on my past chapters!



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I swiftly walk across the courtyard, the taste of cock still lingering on my tongue. I glance across the area and notice it's mostly empty now that the morning lectures are over. I look for Jamal since he's one of the only people I even know, but he's gone too. I take my phone out to check the time and see that it's 12:16. I guess I sucked cock for longer than I thought, 15 minutes felt like only 15 seconds. I have 45 minutes to kill before I can meet with Mr. Gibbs, and my adrenaline is pumping after what just happened in the bathroom. I keep getting satisfying shivers up my back when I think about it, but I can't help feeling like I missed a great opportunity to feel a real cock in my ass.



Once I get past the courtyard I see a girl in a short skirt with a big round butt walking on the sidewalk across the street. My mind seems to go into shock mode. She's incredibly hot, and so the remaining masculine side of my brain is thinking about fucking her, but the feminine side is remembering that my little clit couldn't do a thing, and that I have a better butt than that girl anyway. Rather than have a mental fight, I just do what feels natural. I push my butt out, pull my skirt up a little to show my underbun, and start walking in a way that shows off my hot, tight, smooth body. I can feel men looking at me, thinking about what they would do to me given the opportunity. I walk down the street winking at guys and watching bulges grow in guy's pants. All this attention makes me so horny, and suddenly I completely transcend the guilt I feel about flirting with men. Now all I can think about is finding a cute guy and getting him to plow my ass as soon as possible.



Walking down the street, I'm approaching a small park. I notice a few benches, and someone catches my eye. I see a young handsome guy; he has dark brown styled hair, a hot trimmed beard, and he's reading a book while sitting on a bench. I look at him with more interest as I get closer, and see that he has a strong jaw, and through his shirt I can see his big biceps. My feminine urges take over, despite my inner objections.



I arrive at his bench and sit down. I pull my skirt up slightly when I sit so that it's just my bare bubble butt contacting the bench. The sun has been heating the wood, and the warmth feels amazing on my skin. I can see the guy peek up from his book when I sit next to him, and I can see his eyes wander down. He gets a good look down my shirt, and his eyes trail down to get a view of my smooth legs and the side of my shapely ass. I take out my phone, pretending that I hardly notice this hunk right next to me.



I peek up at him, and he quickly moves his eyes back to his book. I giggle to myself, and use my phone as a mirror to make sure my makeup looks okay. I can still taste cum on my tongue.



"Do you wanna hook up?" I say, still looking down at my phone. I can see him in the corner of my eye. He looks up from his book, surprised, and then looks around to make sure I'm talking to him.



"What was that?" he asks, a bit shocked.



I look away from my phone, and at him. I give him a coy, sexy look, and say, "Do you wanna hook up? I'm ridiculously horny, and you're ridiculously sexy." I look back at my phone, pretending his answer doesn't matter. I'm not exactly playing too hard to get, but I have to at least not appear so bold.



He puts his book down, looks at the cover for a second, looks back at me, and then says, "My apartment is just up there." He points to a third floor window in a building across the street. I look back at him.



"Then what are we waiting for?" I can see a bulge in his pants. My clit is dripping wet, so wet that some of my juices are dripping down to my ass. I'm so horny that I can hardly see straight. He takes my hand and walks me across the street with him. Walking with him makes me realize how much bigger than me he is. He's tall and well built, I'm sure his cock will be the same way.



"My name is Tom by the way." He says, unlocking the door.



"I'm Nellie." I say cutely, looking up at him.



"Nice to meet you, Nellie." He says, winking at me as we go through the front door of the building. He waves me ahead of him, so I go up the stairs before him. I make sure he gets a good look up my skirt as he follows me up the stairs. I'm sure he can see my whole ass, and the wet spot around my clit and boy pussy. I get hornier and hornier as we go up the three flights of stairs. Once we get to the front door of his apartment he looks at me and slowly inserts the key into the lock.



The moment we're inside his apartment, he's on me. Before the door has even closed my tongue is in his mouth and his strong hands are groping my ass. I wonder if he can taste the cum on my tongue. He gives a small slap on my ass as we're making out, and this puts my mind into overdrive. Without even thinking about it, I start clumsily unzipping his pants. I'm moaning lightly as he keeps groping my bubble butt, and lightly spanking my eager ass. When he starts to realize how much I like it, he starts slapping my ass harder. Soon, he has one arm wrapped around my waist, his tongue in my mouth, and his hand reddening my butt with the hard smacks of his palms. I'm moaning hard, and finally I get his pants unzipped. I reach down and pull his cock out of his boxers. I pull my mouth away from his and give him an innocent, sexy look. He nods to me, and I look down. His cock is amazing. It's long, thick, and has these hot throbbing veins that show how much he wants my perky butt.



Without hesitation, I get down on my knees, pausing for a moment to take in the beautiful sight of his big dick before I start sucking it. He grabs the back of my head, and slowly brings my eager mouth towards the head of his throbbing cock. I look up at him and make eye contact, I know how much guys love that, and let him guide his cock into my wet mouth. I know that I could take control and blow his mind with my cocksucking ability, but I want him to feel in control. I'm just his sissy fucktoy.



Once the tip of his dick has passed between my wet lips, I start to suck his cock and twirl my tongue around the head. He gives a satisfied groan and eases up the grip on the back of my head. Of course, I see this as an opportunity to take over and begin working my way down his cock inch by inch. I swirl my tongue around his thick dick the whole way down, getting it nice and wet. I love the feeling of his hot flesh and pulsing veins on my tongue and lips, and I eagerly suck his cock deeper so I can taste it better. His dick even smells good, it's almost intoxicating, and I can feel myself getting drunk on his cock.



Soon his dick is poking the back of my warm throat, and he moans hard again realizing that I'm deep throating him. I'm not done yet though, and try something I've only practiced on dildos. With his big cock in the back of my throat, I stick my tongue out and start licking his balls. This makes him groan hard, and I can feel precum start to leak from the tip of his dick and drip right down my throat. I look up at him, keeping eye contact as I lick his balls and milk his cock with my mouth. His cock is throbbing hard in my mouth, and I know if I keep this up I'll make him cum with ease. But that's not what I want. I have a burning, aching sensation in my ass, I can feel my pussy pulsing and throbbing, just begging for a cock.



I slowly pull my head back, licking his cock and making sure it's soaking wet with my spit. Once his dick is out of my mouth, I look up and ask, "So... do you want to fuck my ass now?" I say excitedly, flashing him an innocent smile.



He seems to have been enraptured off in bliss, just as I was with his cock in my mouth. My voice pulls him out of his trance, and he instantly responds with a deep, "Oh fuck yeah."



He reaches down, and with his strong arms he picks me up and throws me over his shoulder. I'm giggling, he's so much bigger than I am, and he gently tosses me onto my stomach on his bed. I lay on his bed with my legs spread, my skirt bunched at my waist, waiting excitedly for what he's going to do to me. I push my ass up just off the bed, and without a moment to spare he grabs my thong with one hand and pulls it off. "Mmm, didn't know you were trans" He says. He pauses, which makes me worried, but then he gives a light chuckle and says, "Although that little dick is so small it's basically a clit." I breath a sigh of relief. "I'm only interested in that hot ass anyway." He says, which makes me quite literally melt.



Without warning, he pushed his face between the cheeks of my ample ass. I can't help moaning at the unexpected blissful sensation. He tongues my tight pink ass, teasing me by twirling his tongue around the edge, pausing, and then burying his tongue deep inside me. I grab the sheets and squeal as he eats me out. He grabs my cheeks and spreads my ass wide so he can get his tongue deeper inside. He gets my pussy nice and soaking wet with spit, sometimes even spitting on my ass and then rubbing it around with his tongue. Having my ass licked is so new to me, and it makes me light headed. He seems to be enjoying it as much as me, he gives deep sexy groans into my puckering pink hole as he keeps assaulting me with pleasure.



Suddenly he stops, and I feel a sensation of loss when his tongue leaves my pussy. Quickly though, he reminds me of what I really want when he pushed the tip of his big dick right against my hole. I'm so horny, my boy pussy is so wet, his cock is so wet, and my practice with the dildo before causes him to slide right inside me with ease. I can feel the head of his amazing cock pop inside my ass, and then he starts slowly pushing further into me.



In complete bliss, I squeal, moan, grab the sheets, and my body starts quivering at the feeling of a real throbbing cock finally penetrating me. I can feel his cock stretch me out as he goes deeper and deeper inside, and it doesn't take long for him to bottom out inside of me. I'm filled with pride as I hear him moan as he fills me with the whole length of his girthy dick. Once he's all the way in, I clench my ass repeatedly, milking his cock with my tight pussy.



"Ready?" He asks me. I'm rather confused.



"Ready for wha—" I'm cut off mid sentence as he starts pushing his dick in and out of me forcefully and rapidly. "Ho-o-o-ly shi-i-i-it" I say, my voice undulating each time he thrusts into me.



"Oh yeah, that's what you want, isn't it." He says, not even asking as a question, because he knows it's exactly what I want. He grabs my butt and spreads me wide so he can watch his thick cock penetrate me over and over again. I'm in heaven, I can feel my eyes rolling into the back of my head as he assaults my ass with his dick. I can hardly form words as I feel my first orgasm as a girl getting close. The pressure builds up from inside the pit of my stomach, and then spreads. It builds with every stroke until suddenly my whole body is shaking and my ass is clenching hard on his cock, as it forcefully thrusts in and out of me. I grab the sheets and scream into the bed as my whole body is rocked by this man's gorgeous dick.



His cock repeatedly hits my g-spot, and my orgasm continues as I cum harder than I ever did as a man, and I don't release any cum. Tom keeps fucking me hard without pause, and as my second sissy orgasm floods over me I'm thankful for his stamina. He keeps pounding me until I've cum four times, my ass pussy clenching on his dick harder every time, and my clit releasing more precum each time. The fourth time, I cum a lot harder, discharging a lot more precum than before. When I look down, I realize I actually did cum, real cum, just from the anal assault. I finally feel like I've finally cum like a real girl does. Eventually, he tires out but still hasn't cum.



"Awww, you still haven't cum yet!" I say as he pulls out. I sit up on my knees on the bed and pout at him.



"Well you kept cumming, so I tried not to cum so I could keep going." He says, winking at me and falling onto his back. I eye his long cock, it's covered in spit and is throbbing hard.



"Aww, you're so sweet. Well now it's time for me to return the favor, isn't it?" I say, grabbing the shaft of his cock and teasing the head with my other hand. He throws his head back and groans. I try to think of what to do next. My ass is still pulsing, somehow still eager for more, but his dick does look delicious. "What do you want me to do? What would really blow your mind?" I ask, winking at him.



"Well, there is one thing most of my girlfriends have never wanted to do." He says, sitting up and touching my leg, giving me a good view of his sexy biceps.



"Anything" I say, looking at him coyly. Without a word, he grabs my legs, and pulls me to the edge of the bed.



"Put your legs up by your head" He says, reaching into his nightstand. I dutifully obey, and can see him slathering lube all over his hand. I feel so exposed with my legs up like this, my ass is totally open for him. "Just relax, you'll love this." He says, as he pushes three fingers into my boy pussy and starts slowly moving them in circles. So far he's right, it feels amazing as he fingers my ass.



Slowly, he adds another finger, and starts pushing his four fingers into me deeper and deeper. He fingers my pussy soo damn well, and soon I'm practically panting for more. He looks at my face, and sees how much I'm clearly enjoying it, so he pushes his lubed thumb into my ass as well. It feels a bit tight, but so sexy to get stretched out by his fingers like this. He pushes them in and out of me like he did with his cock, and I can feel him go deeper and deeper.



It doesn't take long for him to be almost knuckle deep, when suddenly, without warning, he drives his five fingers deep inside me. I gasp at the intrusion, but my ass has already been stretched so much it easily handles his fist. He groans once he gets his fist into me and starts pumping his cock with his other hand. "Mmmh, I think fisting is so hot, you're so damn sexy." I look at him, my mouth open, and moan as he keeps lightly pushing his fist deeper into me, in and out.



"Mmm, yeah, you like that?" I ask, looking down at my stretched pussy and biting my lip.



"I-I'm gonna cum" he says, jacking off hard and staring at his fist going in and out of my boy pussy.



"Oh! Cum in my ass! Please?" I beg him, I want to feel real cum in my ass so bad.



"Oh yeah, oh fuck yeah" He says, pulling his fist out and replacing it with his big dick. He pushes in and out of me twice before releasing torrents of cum deep inside me. I grab his big arms, gasp, and moan as he pumps his thick cum into my desperate ass. He cums hard inside me, and soon pulls out and collapses onto the bed. I spread my bubble butt and watch my ass as I slowly push his cum out of me.



"Mmmm, oh that was so good, that was so damn good." I say, falling onto my back onto his bed.



"Oh yeah, that was really amazing." He says, sitting up. I look him up and down, taking in the view of his chiseled abs and chest. "So, how much do you charge?"



"Huh?" I respond, confused about what he meant. After two silent seconds I realize what he's asking. I am a bit low on cash lately, and consider telling him $200, but my little remaining masculinity gets the better of me. "Oh, heh, I'm not a prostitute. I just really wanted some dick" I say, winking at him.



"Heh, I see." He says, before reaching over to his nightstand again. "Well then consider this a token of friendship." He says, as he puts $300 between my perky tits. I can't say no to that.



"Mmm, well if that's the kind of money I get for cumming four times, maybe we should do this more often." I wink at him. I keep looking at him a little longer, trying to take in the view of this hunk a little longer before I have to leave. I stand up, pull my thong over my cum and spit soaked clit and ass, and put my micro skirt back on. We get dressed together, he puts on some jeans as I put my shirt back on without a bra. He leads me to the door of his apartment and gives me a passionate kiss before opening the door.



"I'll see you again sometime, you sexy thing" he says, giving my ass a little squeeze before I step out the door.



"Oh don't worry, I'll be back for a ride on that nice cock of yours real soon." I tease, winking at him before he closes the door. I take my phone out of my pocket and check the time.



"Oh shit." I murmur to myself. Every time I have sex, or suck cock, time seems to fly. It's already 1:55, which means Mr. Gibbs lecture has been over for almost an hour already. I rush down the stairs, out the door, and back onto the street. I can feel cum still dripping from my ass as I walk down the road. Hopefully it's not noticeable, but with my short skirt and small thong, I doubt it's very inconspicuous.



Nevertheless, I make my way down the street towards the school. This is my opportunity to finally undo this body transformation. This makes me pause and slow down, do I want to change back? "Pshh, of course you do" I whisper to myself. "All that sex and flirting...it was just the formula!" I reassure myself. "Yup, just the formula." I walk towards the school confident in my decision to change back. I can feel my resolve waver as my horniness builds up again. Feeling cum dripping out of my ass, tasting cum on my tongue, and seeing guys checking me out makes me reconsider over and over again. Should I change back? Each time I ask myself my masculine side responds, "Yeah, of course." I say it to myself to make sure I remember, I want to change back... I think.



After a few minutes, I approach the science wing of the campus. I hope Mr. Gibbs is still there. I quickly and quietly make my way up to his room. Most of the lectures for the day are over, so I have little difficulty in not being seen. Once I get to the third floor, I quietly scamper through the halls towards the labs. Once I'm close, I realize I don't actually know which lab is his.



"Hey there Nellie." I hear someone say from behind me. I turn to see that it's Mr. Gibbs, he's poking his head out from one of the doors.



"Oh, hey Mr. Gibbs!" I chirp, excited that I didn't need to run around trying to find him.



"Please, call me Charlie. Come on in, I'm glad you decided to come here to see the lab." He says cheerfully, opening the door wider for me.



"Yeah well I was afraid you had already left, since it's an hour after your lecture." I say, following him into an office. There are rows of black lab tables against one wall, and a line of cubicles with computers on the opposite side. Another wall is glass through which I can see the room where they seem to keep all the expensive equipment.



"Oh don't worry about that, I'm usually here conducting research long after I finish my lectures" he says, chuckling a little bit. I giggle a little as well, which eases any tension I was feeling. "I have a few things to show you that you might be interested in here" he says, opening the door to the room with lots of equipment. I can feel him watch my ass as I walk through the door.



"Awesome, hey thanks for letting me come up here, I've never had an opportunity to see the third floor before." I say, turning and smiling at him.



"Oh it's my pleasure to show students who are interested, but we can both drop the act now can't we Nellie?" He says, taking a slightly more serious tone. I freeze, but try not to let my face show my panic.



"What exactly do you mean sir?" I ask, trying to look legitimately confused.



"Well, I know that you and Claire are roommates." He says, closing the door behind him. "She's a very bright student you know. She has a real knack for genetics, and so I allowed her to help me on one of my most recent projects." he says, pacing back and forth, almost like a mad scientist. I watch him quizzically, and notice that he's changed clothes since I saw him in the subway. There he wore a brown suit, which made him look more like a professor, but now he's wearing a muscle shirt and slacks, which make him look kinda hot. I zone out for a second and miss part of what he's saying.

