When you get goose bumps when you need to pee.
e.g. "Whoa! Look at my arms -- piss shivers! I need to pee..." Joe
That annoying little shiver you get at the end of a long and refreshing piss.
Damn that piss shiver gave me the chills!
The feeling experienced when a person (perticularly male) urinates; can be used colloquially to describe any other experience which causes the same or similar feeling.
The bridge of that song gave me piss shivers.
Shaking randomly when your pissing :P
Monty: "I was the other day, and i shivered! Piss went everywhere!"
Assface: "Thats called Piss Shiver -.-"