“Pay up!”

You made a bet with your friend about a baseball game. You just won the bet, so now you want your friend to pay you the money that he owes you. You say:

Pay up!

Pay up!

This is a phrase that you say to make a friend pay you after you win a bet. If you used it with people you don't know well, or with your friends in other situations, it might seem rude. But it's a perfect phrase for friendly bets.