1.) The art of buying a Mcdouble at McDonalds, going to the bathroom, splitting the sandwhich, jizzing on a patty, and going up to someone whacking them in the face with both ends of the McDouble.

2.) When A male gets a casual Handjob in McDonalds from a random female.

Originated In State College, from the Classic S.S.F.
1.) "Oh my God, Leanne just got a McWhack-Attack from that guy in the panda suit!"

2.) "Every Friday, I got to McDonalds SMASHED at 3 in the Morning and get a McWhack-Attack from all the prostitutes.
Get the McWhack-Attack mug.
the act of getting dbagged or getting called out on a bold statement
Parker Allen: The packers are going to go 0-16 this year!
Worder's Whack: Hey didn't the packers win today making their record 15-1?
Parker Allen: I just got mcwhacked!
by whack off king November 30, 2005
Get the mcwhacked! mug.