Alyson Hannigan's children will not be following in their famous mother's footsteps any time soon. The "How I Met Your Mother" star was just 4 when she made her acting debut in a 1978 Duncan Hines cookie mix commercial -- but she says she won't allow her kids to do the same if they're enticed by the bright lights of Hollywood at a young age. "I definitely would want them to wait," the actress, who is due to give birth to her second child in the spring, tells omg!. "Saty [daughter Satyana, almost 3] is sort of the prime candidate for acting … so hilarious and so expressive." And she can even cry on cue! "Early on, I think she was just over a year and just starting to talk," explains Hannigan, "she was in my closet and she was looking at herself in the mirror. She was really close up and studying [herself], and then she started to tear up. I was like, 'Honey, what's wrong?' And she says, 'Look, Mommy, I'm crying!' I was like, 'Oh no, we're doomed,' but she was so pleased with herself that she could make herself cry. So she's certainly showing signs, but we're going to keep her being a kid for as long as possible."

The only role Saty is looking forward to for now is becoming a big sister -- and helping her mom get ready for the big arrival. "She's so excited" says Hannigan, 37, who has been married to her "Buffy" co-star Alexis Denisof since 2003. "She talks to my belly all the time and wants to rub the lotion on my belly. The problem with a nearly 3-year-old rubbing lotion is that she uses half the container for one session. The body butter budget has gone up!" The little one is also giving her parents advice on what they should name the baby, but some of her ideas are just a little too out there, even by Hollywood standards. Although she likes Coco for a girl, "If it's a boy she wants it to be Gaguzzi because it sounds like Jacuzzi," says Hannigan with a laugh. "I'm all for the unique name, but that's just going a little too far."

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Pregnancy this time around has been a much calmer experience. Even though she's been busy working and chasing after Saty, now Hannigan feels like an old pro and isn't concerned about every little strange thing she feels. "I'm like 'yeah, that's normal,'" she explains. "I also feel like this baby is a lot more mellow. Not that Saty was an active baby, but my cravings were super strong. And this one, I definitely see that my eating tendencies are different. I'm not going to push somebody down to get to whatever I need to eat." Hannigan is also craving healthier fare, too. "I'm really enjoying citrus fruits and trail mix," she adds. "I feel like my sweet tooth has diminished."

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As she prepares to welcome a new baby -- and lots of dirty diapers -- Hannigan is focused getting her daughter potty-trained. She's even partnered with Pull-Ups to encourage parents to do it in a fun way -- with the nationwide Potty Dance Party movement. "If you can make something fun, it will be a lot easier for everyone," she recommends. As for Satyana, "She's been doing fantastically well," brags the proud mom. "We've had some accidents, but that's to be expected."

The most memorable one? "We were in Atlanta, I was there filming 'American Reunion,' and we were in the grocery store, and she said, 'Mommy, I have to go potty.' So we go to the grocery store bathroom, which was immaculate by the way, and she said, 'No, I don't want to go on that potty.' I think it was because it was one of those automatic flushers, which is scary. So we're standing like two feet from the potty and I'm holding her on my hip, trying to talk her into it and she peed all over me." But although Hannigan and her daughter were both soaked, she sprang into mommy mode with little drama. "I washed the two of us off, immediately left the grocery store, went out to the car, put a Pull-Up on her, went back, and finished the grocery shopping. Thankfully it was the summer in Atlanta so my dress dried off pretty quickly."