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