[screaminggood]

Oh, one of our specialities....we've done beaches all over the world. Isn't that what they're there for?

Correct beach version:

Put down clean towel. Put clean man on towel, lying on his back. Have woman straddle him and go for it.

....and you can always do it in the shallow water! Sand washes off....just get used to the barracudas eyeing you!