The Adventures of Tracy Dick- The Case of the Missing Stiff (1985)
A silly plot with a sex detective (Traci Lords) is called upon to get the rich guy to reveal the heirs to his fortune. Early sex scene with a nebbish like assistant Tom Byron gets the movie off to a good start. Eventually Traci gets to the house of the rich dude but never has to have sex with the guy to solve the case. Instead Traci has her usual encounters with a guy (Peter North) and a lesbian scene.
Jodie Foster checking you out while she is nude sitting in her hot tub
Jodie Foster nude in a hot tube, looking back at the camera