Throw a piss 

Urinate

Dude, where’s the head. I gotta throw a piss.

Throw a piss by the comand'r November 29, 2019

Throw A Piss 

The act of urinating

"Jillian, hold my Champagne flute, I have to 'Throw a Piss' in the lavatory"

Throw A Piss by Joel Jackson January 2, 2008

throw a piss 

Take a piss.

Man, I've got to throw a serious piss.

throw a piss by N Jacobs June 23, 2004

Throw down a piss 

The act of urination by persons who announce this phrase.

"Hey everyone, I'll be right back, I have to throw down a piss." or "Pardon me, but I must throw down a piss immediately."

Throw down a piss by BassActionBastard February 25, 2010