Venus Descending (1997)

Two beautiful women from a distant planet, Althea and Kika, search for a Kama Sutra type book, revealing hard sexual secrets. They encounter one sexual situation after another... finally, Eric discovers (after making love to Kika on a beach) that she has been sent to earth to find this ancient book. Althea, Kika's adversary, finds the book first, however... and uses it to create a device that can turn women into obedient slaves by using sexual stimulation; some spanking is added to the mix.