rather than 1 person throwing a rubber ball at the other 10+,
wah-ball involves 10 or more people throwing tennis balls or rubber balls at one person - the "wah".
Tennis ball guy: Lets play wah-ball.
Geek: No, I'm always the damn wah.
Randomer: Lighten up JM, wah-ball rocks!
Geek: Have you ever been the wah? didnt think so.