Stand naked in the corner of a room with arms extended like the hands of a clock while rocking hips side to side to slapone's balls against his thigh rhythmically with every second
Uncle Lester got drunk again on Thanksgiving and did the grandfather cock in the corner of the living room for hours until my mom finally called the police
When you're trying to shop for some antique grandfather clocks for your paps but then you unfortunately forget the "l" in "grandfather clock" and now you wish you were dead.
Poor Fool: *mistakenly types 'grandfather cock', clicks on 'images'*
*questionable things appear*
Poor Fool: AH DEAR GOD GET THE BLEACH
sex move used by a male to pleasure two females at the same time. have the two females face away from you, one in the front and one in the back. place a strap on dildo backwards so that it is facing the girl behind you and also erect the penis towards the front girl. then rock from back to forward once every second.
when one finds themselves in the middle of a threesome and out of ideas, it would be wise to wip out The Ole Grandfather Cock.