This is something I have done, with a girl through another peeing related site. We discussed how we would do it before hand and then went to a private chat session to act it out. Basically we drank quite a lot of fluid prior to the start. Her thing was holding until she wet herself, mine peeing on command. So basically the two of us are online and she is driving the scenario as coffee after a date, leading up to sex. She held on until she could wait no longer, told me what was happening, and then I was told to pee, which I did. this culminated in a masturbation session.
It was a worthwh