All of Me
All of Me (1984) is a supernatural comedy film directed by Carl Reiner. It stars Steve Martin, Lily Tomlin, and Victoria Tennant. (Martin and Tennant were married from 1986 to 1994.)
Martin plays a lawyer who becomes possessed by the spirit of a recently deceased client (Tomlin). She controls the right side of his body. He is constantly struggling to regain full control of his movements and speech. Much of the comedy comes from her forcing him to say and do things against his will (and contrary to his nature). Things get even more complicated when he has to deal with a scheming vixen played by Tennant.
The spanking scene
In a bedroom scene, Tennant tries to seduce Martin. Tomlin's character is outraged and forces Martin to call her a "cheap sex tramp" who deserves "a good spanking". Martin can't control his hand as he starts paddling the lingerie-clad Tennant as she kneels on the bed.
The humor of the scene comes from Tennant mistaking this for a sexual role playing game. Immediately aroused, she begs for more spanking and "dirty talk" insults. Tomlin soon stops the intended punishment as she realizes Tennant is enjoying it.
A video clip of this scene is at Dailymotion.