I'm gay and noticed other guys at the gay club also holding it until they can't hold it anymore or have to block it to keep holding and talking with the other guys at the club. Its fun go go dancing when your bladder is full, it's a really good feeling and I'm often getting hard when my bladder is full. 

there was not enough time between classes so they would use the sink to go,     if you could not get to a open one, you held it. went back into the hall, filled your water bottle and went to next class. got really good at holding as a result. 

I love it when a guy is holding it back by squeezing his dick inside his shorts or squeezing through the shorts. or pressing between the legs to block it.  I have done it myself at the clubs a lot. easy to reach in loose shorts and block it or through them if they are thin fabric.   urge to pee will go away after a while and bladder will relax again and can keep drinking beer without pissing. if at a gay club i am shirtless and my abs will pop when my bladder is contracting hard and my abs are pressing in hard on my bladder. if another guy is busting i will see if i can get him to hold it with me.

In a beer can on a very crow ded train in front of all my friends!! 😀

will the birthday boy and his friends have all been drinking a lot of water and are busting for a piss and good at holding and holding a lot?? it could be a tradation where the birthday boy has to have sex with his bladder really full. maybe he and his friend's are not allowed to pee until the end?