Full Cavity Workout

Giving a Wet-Willy to your partner then retrieving the finger before it gets too deep and is lost, drenching the finger in piss, coke, or whatever else you please, then maneuvering it about the anus, being careful to not be sucked in by it, and finally, making them get a full whiff of its scent, by placing your finger on the inside of their nostril, and there you have it, all of the exercise you'll ever need. Amen!