A Brain Giggle. It is a more authentic response to something funny than LOL. The Brain Giggle describes an internal response to hilarity, producing at the most a smile, but no actual laughter. To discuss BG's with a friend often sounds much less innocent than it actually is.
“Dude, did you see what Sarah posted on her Facebook?”
“Yeah, man, I BG’d so hard.”
“Weren’t you sitting with your parents?”
“I BG in front of them all of the time.”
From the French abbreviation "Beau Goss" meaning beautiful, handsome man. This abbreviation is often used to refer to a boss playa. He is man that owns respect from from all fellow BGs. His other bros wanna be a BG like him and try very hard to achieve this legendary alpha-male status.
Peter is such a douche, he hooked up with rebecca and now he's ignoring her." "No no no my friend, that is not a douche, THAT is a BG.