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? 

did you swim with your bladder full??? drink a lot before pissing? have you held your dick to build up pressure other times? I like that feeling and have done it a lot of times. even done it without peeing afterwards. 

did you swim with your bladder really full? how much did you drink before a swim meet? ever showed off how big your bladder got? did the others hydrate well too?? did any horsing around while bladder was full? have you held it other times seeing how full it could get?? I would hold it in class and go to next class still holding.