While Justin Timberlake has always been cool about putting his junk in a box, another Justin, with the last name Bieber, was less comfortable singing about his own stuff in a "Saturday Night Live" digital short.

Playing the part of Lonely Islander Akiva Schaffer, alongside Jorma Taccone and Andy Samberg, the teen pop superstar helped the comedy trio celebrate their 100th digital short. The skit opens with the three guys, including Bieber, who confuses the name Akiva for the sound of a sneeze, introducing their A-lister-filled skit, complete with appearances from Timberlake, Michael Bolton, Usher, Jon Hamm, Will Ferrell and Natalie Portman, as well as character cameos from Shy Ronnie, Jack Sparrow and Sergio the Sax Man, to name a few.

In tuxes, the three Lonely Island guys (with Akiva as imagined by Bieber) dance around congratulating themselves on the achievement, listing off all the ways they will celebrate (pilates included!). But, as it turns out, Bieber will do anything but he won't do that. And, what exactly is that? Well, you see the guys want to "suck our own d---s."

Bieber's response? "That's disgusting."

While Bieber stands as a highlight, so do the Timberlake and Portman cameos in the sketch. Timberlake was back, d---s in boxes and all. Meanwhile, Portman, holding a doll baby, got her gangster rapper on again, proclaiming, "Yeah I had a baby, but I'm still crazy."

As the short nears its wacky end, Bieber shares, "I was tricked into doing this. I don't endorse this song. No, no, no, no." Of course as he says this, Hamm as Sergio air humps around him.

In the end, all of the characters get in a room and the guys (with Akiva now in for Akiva) once again share that they will celebrate the way they always intended: by sucking whatever it is they want to, 100 times.

Saturday night's episode was hosted by former "SNL" star Will Ferrell with musical guest (and Bieber's mentor) Usher on hand. The finale airs this week with Rolling Stones leading man Mick Jagger hosting.

What's your favorite Lonely Island digital short? Leave your comment below!