Rosalyn Sphinx has a rare condition that makes her to have wild, enormous orgasms that she can't stop from coming. Her stepbrother Lucas Frost feels this is a challenge, since each time Rosalyn cums in front of him Lucas gets a huge hard on. One day Lucas' dad Dick Chibbles, notices Lucas looking at his stepsister with wet, bedroom eyes one day in the living room and kicks Lucas out, before Rosalyn get the idea into her head that fucking might cure her problem. When Dick dozes off in front of the TV, though, Lucas sneaks back into the living room to be seduced with Rosalyn making the exact moves Dick feared she might...