Caught from Behind 2 (1983)

The second edition of the anally obsessed series once again brings us the amorous antics of Dr. Proctor, this time played by Eric Edwards in a daft performance. Edwards brings in a string of sexually troubled patients and somehow comes to the same diagnosis for each of them -- what they really need is a hefty dose of anal sex. While this doesn't go down too well with some of the gals, the good doctor makes sure that he teaches them everything they need to know about back door boffing.