My Wife Caught Me Assfucking Her Mother - Alli Kendrixx, Danica Dillon & Zack Ryan

Alli is furious to discover her mom's previously worn lingerie hidden in her bed. Why would they be lying there? Is her mother sleeping with her boyfriend? Naturally, Danica denies any wrongdoing, but eventually Alli witnesses them in the middle of the intimate act. With a man's member completely inside her backdoor, Mom is revealed engaging in intense carnal activity.
How do you justify this? Mom explains that she is teaching her boyfriend how to properly administer anal pleasure to Alli on her birthday. Isn't that special - mommy certainly holds the expertise.