The grenade is an alternative sexual manuaveur, it begins with the basic handjob. When the man begins to orgasm however is where the grenade differs because the one handjobbing makes a fist around the erect member and clamps their thumb over the penile orfice. This is usually followed by a yelp by the man because of building pressure and is usually released quickly with a explosion of white male secretion.
Me: Hey dude why are grabbing yourself?
Mike: My girl gave me the grenade because I called her Heather half way through.
Me: Shit thats some mean and cold hearted shit right there.
Noun: An improvised weapon of the feline variety. A cat grenade occurrs when one (or more) cats is/are picked up and hurled at the offending party. The Cat Grenade is the preferred weapon of the insane, meth addicts, or the Cat Lady featured in the Simpsons cartoon series.
When a guy hasn't jacked off in a really long time, so he has two "hand grenades" in his pants. He uses his hand to 'pull the pin,' and the Hand Grenades explode, ejecting 'shrapnel.'
Dude, I didn't jack off for like a week, and when I pulled the pin last night, my Hand Grenades EXPLODED!!!!!