When a girl is giving you a blowjob, and your best friend is hiding and watching, and becomes visible to the girl and the best friend gives you a thumbs up while you get off.
"holy crap that feels so good. I'm about to get off, it's going to be a brogasm..."
Girl- "What?"
Best Friend- "Way to Go!!" (give thumbs up).
by j-squared314 March 20, 2011
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A feeling of excitement brought on by a though or act of a brotastic moment.
Bro 1: I can't wait to chill tonight man.

Bro 2: I know, I'm 'bout to have a brogasm just thinking about it!
Bro 1: Its gonna be brotacular
by Broseph Manly August 6, 2013
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