by Chicken83 April 02, 2007
When you absolutely plough the shit out of the side of someone's thigh with your knee, hence named because they will be walking like a grandad for the rest of the day.
by Frankoyo December 02, 2013
An exclamation guaranteed to cause confusion and possible upset, particularly when used during coitus.
Man: "Oh yeah baby.....Mmm hmmm..."
Woman: "Oh yeah, oh yeah, oh yeah...."
Man: "Uh, uh, uh, uh...oh yeah....oh fuck...I'm gonna...I'm gonna...GRANDAD!!!!"
Woman: "WHAT THE FUCK IS WRONG WITH YOU?!?! Get off of me and get the fuck out of my house you sick freak!!"
Woman: "Oh yeah, oh yeah, oh yeah...."
Man: "Uh, uh, uh, uh...oh yeah....oh fuck...I'm gonna...I'm gonna...GRANDAD!!!!"
Woman: "WHAT THE FUCK IS WRONG WITH YOU?!?! Get off of me and get the fuck out of my house you sick freak!!"
by The Mongo Collective January 09, 2008
you knee some innocent sole in the thigh
it hurts
and afterwards they walk like a grandad.
this is the concept we all know and love.
it hurts
and afterwards they walk like a grandad.
this is the concept we all know and love.
by Charley351 November 04, 2007
where somone hits someone else in the area above the kneecap on the side of the left leg with their own knee. why? because its bloody funny (only if it works)!! the consequense of this will be the other person hopping on one leg shouting swear words,while u and ur m8s r laghing like hell. also some advice: always give a grandad when the other person is noot expecting and make sure u r standing up when doing it. there are adaptions of the grandad like a 'running grandad', the 'spinny' and a 'flying grandad'.
by Mikey November 08, 2004
by Steelbeast November 01, 2020
by grandads girl LOL January 21, 2009