A sex move, whenever you blow your load in someone's face or frontal area unexpectedly, you yell SHWAM! at the top of your lungs. Then tell them to clean up.
A word you yell as an extremely hot chick passes by, followed by a pelvic thrust in here general direction. Originated from the movie Waynes World 2 by Dana Carvey.
Vince: Man that chick is so fine!
Wes: Show me your tits!
Cj: SHWAM!