While “take a leak” is in print only from 1918, the term leak meaning “to urinate” goes back to at least Shakespeare. 1596. “We leake in your Chimney.” Henry VI
Info from my Lighter. .
How about “make shit” or “make piss”?
syphon the python
point percy at the porcelain
trace terrance on the terra cotta
and my all-time favorite:
shake the weasel
I feel drained by this entire conversation.
Sit down when you want to pee, and Never Whistle While You’re Pissing.
A little limited in applicability, but variations on this are sometimes seen above the urinals (and sometimes heard) where guys are working on airplanes:
“Aircraft with short pitot tubes and/or low manifold pressure, please taxi up close and don’t sump on the floor. Not all pilots operating here are seaplane rated.”
Definitely limited applicability. Ever heard anyone say “Gotta go sump”?