A nutsack with an extreme amount of dangle in its angle. Usually used to describe such during periods of warm weather when someone decides to go commando.
If i accidentally sit on my speedbag, it makes me throw up in my mouth a little.
by PeterGammonsLuvChild May 9, 2005
To rapidly bash one's testicles against a girl's vagina or ass when you're fucking her quickly.
I speedbagged my girlfriend so hard last night I bruised her ass.
by Ljo93 July 15, 2008
To repeatedly hit the forehead of the woman who is sucking on your balls as you masturbate, akin to hitting a speedbag with one hand.
I was speedbaggin' Becky and jizzed in her hair.
by Jizzones October 15, 2006
the process of punching a woman's bare breast quickly and repeatedly, just as rocky balboa would go at it with a punching bag.
weeks's mom likes it when i speedbag her.
by chikochan April 28, 2005
1. A chick whose face is straight up heinous, as if it had been assaulted violently, rapidly and repeatedly - the way a small-sized punching bag might be.

1(a). When said chick acts as if she is hopped up on speed or other narcotics, to the point where she is tweaking out and making next to no sense. Can go along with, or be mutually exclusive of, definition #1.
DUDE A: "I can't believe you boned that speedbag last night."
DUDE B: "I know... at least I'd had about 14 beers beforehand, and the lights were out, so I couldn't see that busted grill."
by Marsbag June 6, 2006
The acted of getting kicked/punched in the nuts in a manner that leaves you feeling like someone is using your nuts as a speedbag.
Damn, I just got speedbagged while wrestling with the kids!
by pattyF May 21, 2010