1. The act of masturbating (the
bumping of the tip of the penis) and
fist pumping at the same time. This act is usually done when watching exciting porn or when someone just really likes
Jersey Shore.
2. The act of making the previous definition motions as a dance.
1. Person X: Dude you wanna go down town tonight?
Person Y: Na I
rented a gang bang porn and I think I'm going to cheer on the guys by doing the Head Bump,
Fist Pump.
2. Person X: How are you banging a different girl every other week?
Person Y: I just Head Bump, Fist Pump
like a champ at the clubs.