When you
crack a joke and someone else doesn't
catch on.
A little
flick of the hand in the direction you would naturally bat, while making a "shhhiou" sound with your mouth. Much like when someone does it over their head.
You say "Swing n a Miss" directly after the swing - all in 1 word.
Ryan: Haha, check out THAT
broad broad.
Jim: I think you mean "bored" broad.
Brett: Yeah, because she doesn't have any food!
Ryan:
Hahahaha.
Jim: Huh?
Ryan & Brett: *shhhiou* Swing n a Miss!