In reply to the question, no, I've never had a full-bladder fuck.
I've never met a guy who's been into watersports, though to judge from your site there must be a lot of them out there. The nearest I've come to having "wet" fun with a man was once when I was leaving a pub after an evening's drinking, with a friend called Andy. I knew he'd got several pints inside him and to "torment" him I deliberately hailed a cab for us both (we lived quite close together) before he'd had the chance to get to a loo. As I'd hoped, the cab took a long time to get across London and I could see Andy wriggling desperately in his efforts to hold it in.
Andy asked the driver to stop at a public toilet, but the driver replied "they'll all be shut at this time of night mate". He did drive to one and it was indeed shut, so that simply added more time to the journey. By the time we got to my home (which was nearer than his) Andy was frantic. He was hopping up and down outside the front door as I pretended to search for my key and once we were inside, he broke the world speed record for the race to my bathroom ....
The other day I was talking to a girlfriend called Anna and the conversation turned to pee-related matters. She's not really into watersports herself, but she told me that when she worked as a nurse and her duties included looking after the patients' toilet requirements, she got the impression that on the whole the women had better bladder control than the men. Anna said there were two possible anatomical reasons for this:
Firstly, any flexible container filling with fluid will tend to become spherical and the female bladder is more spherical than the male's to start with.
Secondly, women's abdomens are designed to be able to swell up because of pregnancy, hence more room for bladder expansion.
However, my own view is that women are simply obliged to train their bladders better than men. It's easier for a boy to have a quick surreptitious pee than for a girl. Women's public toilets are often far less adequate than mens' (have you ever joined a long queue for the ladies' in the interval of a concert or play and watched as the men sailed blithely in and out of the gents'?) And even today some women can be shy about asking to go to the loo. What it all amounts to is that almost from day one females have to keep their bladders under better control than males and their sphincter muscles respond by getting stronger and stronger. That's my theory anyway!
Since I last wrote I've had another go at the one-and-a-quarter-litre mark but without success I fear - perhaps next time ...