a phrase that someone says after they had done something extremely extravagant, or is trying to talk trash to the opposite party; synonym for "bring it on" or "try to top that, bitch!"
Person 2: Stop being a cocky-ass, you c**t!
a combination of "get some" and "come at me"
used specifically to show how much better you are than other people.
Its also possible to use this phrase in a sexual manner, although rare.
Tom: 25-0, that's game
Jim: I wanna rematch
Tom: Get at me faggot
ex. 2: (Billy has a crush on Annie)
Billy: Hey Annie!!
Annie: Do you wanna fuck me or something?
Billy: That'd be fun!
Annie: Whatever, get at me