A face on a person that shows no emotion, often called poker face because in the game of poker it would be foolish to show any emotional traits that might screw the game for you.
A 'poker face' is when a guy shoots a load on a girl's face while the girl's expression doesn't change, despite the fact that she loves getting a facial. She keeps her 'poker face' because she knows that if she lets on that she enjoys it, her boyfriend will continually request to give her facialsuntil the end of time.
Damn man, I didn't realize Julia loved getting facials until 6 months after we broke up. I can't believe she poker face 'd me.