His Loving Daughter (1971)

18 year old Gina peeks through a keyhole in her dad's office and watches him get his client drunk and take advantage of her. This gets Gina all horny, so Gina calls her boyfriend for a hook up. The problem is, he can't get it up! So, she seduces the pool boy who "teaches" her the ropes, then learns about girl-on-girl Action.

A horny girl sees her widowed mother acting like a nasty cockhound and learns fast how to have fun too.