A method of masturbation in which you take a piece of grass or other thin object (pencil) and slide it into your urethra then out again, as if your were cleaning a pistol. Tends to be painful and only recommended for experienced jack-offs.
Person 1: Dude, did you see that chick last night? She was smokin'.
Person 2: Yeah man, I grassy bored that.
Person 1: WTF is wrong with you?
Person 2: Yeah man, I grassy bored that.
Person 1: WTF is wrong with you?
by Yarrrrrrrrrrr October 13, 2010