I'm going to make a quick phone call.

Oh, dear, I don't have any 10-yen coins.

I've got one!

Close up the palm of your hand and conceal the 10-yen coin in it.

Rub the back of your hand and act as if you pushed out a 10-yen coin from it.

Oh, wow, amazing. A 10-yen coin slipped through your hand! How did you do that, Princess?

The idea is to do it quickly.

People might be surprised if your partner is good enough. "Kaguya's Magic Lesson"