A sexual act in which a woman, during her period, inserts a ping pong ball into her vagina. She then, using muscle contractions, pops the ball out, hopefully causing it to fly some distance.
"Dude, my grandma can rusty cannonball farther than you can throw a football"

"You'll never believe it, but my girlfriend almost took my eye out with a rusty cannonball last night"
by Kirkus Jones February 12, 2007
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A rusty cannonball is when one passes wind into a sheet or an item of clothing and the item is thrown at someone.after the item hits them the item should"explode" and wreak havoc!!
Jimmy:I was chillin with connor the other night when I decided to fart in my shirt and rusty cannonball him.

Sean:aww man that's ruthless!!
by jimbob8jim March 26, 2008
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