Question for the OP. Is she hot? If she is and really will pay me $300 each time, I think I would even if it was in the face, as long as I knew when it was coming and I could work around it to clean up.
Sorry, but it's clearly a "he" in this scenario. It's about being paid for something gross and humiliating. Not fulfillment of some fantasy where you get a golden shower from a super model who's willing to pay you for the privilege.