Just bought a new 7mm and dove it for the 1st time yesterday -
Must admit I had some reservations b/c the suit was brand new, but I said *** and pissed away - at least 4 times!
I don't know how people hold it in - if you are drinking enough water (I drank two 20 oz waters before the 1st dive alone) it happens.
On a somewhat serious note, its critical to drink plenty of water before, and after diving - medical benefits not withstanding, you just feel so much better (almost as good as pissing your wetsuit : )
Most interesting pee story (not that I collect them) concerned a female cave dive instructor - she dove dry but used adult diapers for the inevedable what was going to happen. Makes sense, sure, but Adult Diapers??
And by the way - interesting 1st "meet and greet" post!