When masturbating, cum, but then fap through the orgasm while urinating the whole time. This will leave both semen and piss all over the place. The idea is to get as much pee on the floor, walls, couch, ceiling, etc.
Guy 1: Dude, it smells like piss in here! Is that dried cum stuck to the wall?!?!?!
Guy 2: Yeah, that was some pretty good urojacubation last night!
Guy 1: WTF?!?!?!