A man stopped by to see his friend who recently broke both his legs.

After about an hour of conversation, Mike asks,
"Bill, would you mind running up stairs and grab my slippers for me? Stairs are a little difficult."
"Yea man. No problem."
As Bill is walking down the hallway upstairs he peeked through a door and sees Mike's gorgeous twin 18 yo daughters.
He opens the door and says,
"Your dad sent me up to have sex with you two."
With the look if disbelief on their faces, he says,
"Look, ill prove it to you".
He yells downstairs and says,
"Hey Mike. Both of them?"
Mike "Hell yea, both of them. What good is just one?!"