The urinary & reproductive systems are separate. But as they each exit through the urethra, If the stone is stuck there, ejaculation can force it to be passed. The person fucking (or jacking, etc.) with a stone in their urethra is definitely demonstrating commitment to the game. Hat's off to them.

now i want to rewatch Deadwood

I have absolutely no idea how those things are related but I'm happy to inspire you in any way I can

in the episode Requiem for a Gleet one of the main characters has to pass kidney stones and they unsuccessfully try to milk them out of him😅

See now I’ve snort my morning cup off coffee everywhere. 🤣😅