You lookin’ to get a little naughty in the bathtub? This position is for you.
He sits against the back of a tub with his legs as straight and as wide as possible. She squats over him, facing his feet, and lowers herself onto his penis, while keeping her legs outside of his. Holding on to the edge of the tub for balance, she would then turn on the water and use her free hand to aim a detachable shower-head between her legs. The running water will cascade over her clitoris, adding to the ecstasy.
Talk about doubling your pleasure. She gets simultaneous internal and clitoral stimulation, and her man’s hands are free to fondle the rest of her.