When someone goes to pound their fist against yours, you move to the side and make a peace sign, and if you look at both hands together, you've made a SCHNAIL! You must yell "SCHNAIL!" when this occurs.
Yours is the head of the snail and the other person is the shell. Therefore: snail + shell = SCHNAIL!
An art similar to cock blocking. Where as cock blocking is in front view of the victim, Schangling is somewhat more devious. To sneak over to a girl in a bar or club when the person who was chatting her up,is on a short term absence " smoking , toilet or at the bar". Schangling is an act of espionage carried out from a distance, carried out only at the right time.
How did you get on withthat girl Paul? "No good, she was talking to him when I got back from the toilet, he must of been Schnagling me"