An action. Also known as a "beana". To quickly run your finger, or other objects, through someone's butt crack, while exclaiming "QUABEANA!". Not a sexual gesture.
Different variations include changing the location of the "beana" (I.E. Quabeana-ing someone in the kitchen might also be called a "Kitchen-beana!")
Or changing the beana'd body part (I.E. Running your finger through someone's cleavage may also be called a Boob-crack-beana!)
1. "I can't believe you Quabeana'd me while I bent down to tie my shoe!"
2. While at olive garden, my sister ran her breadstick along the waitress' crack and yelled, "WAITRESS-BEANA!"