Let them compete for it.

Suddenly an idea strikes and I smile.

"Okay girls I've got an idea for how to sort this out. You're both going to get naked. You're going to get into a sixty-nine. And you're both going to go at it."

I grin at the two slightly shocked faces.

"Whoever makes the other one cum first gets their chance with me. The other will suffer a forfeit. Ready?"

A brief moment of glazed eyes and both of both of them are nodding and stripping with hunger in their eyes.