To a-
game someone: To try it on with a
girl.
A persons a-game: Their effort in trying it on OR the person which they are trying to get in with.
a-gaming: Chatting to a
girl with the sole purpose of trying to get in their pants.
The A-Game: the art of trying to pull
A-game ON!: an expression used by others when they spot their mate on the a-game