whoa - this is quite a racy sentence!
Does this mean "are you pulling my leg" or actually "are you playing footsie with me"? Or both?
Shouldn't "Es-tu en train de jouer avec mes pieds?" be accepted as well?
Why does, "Est-ce que tu joues avec les pieds?" I thought in French it was understood which feet you are talking about?
In that sentence "les pieds" could also refer to the other person's feet.