Mother and son have sex in 2 seconds after father goes out

Atsushi has a forbidden physical relationship with his father's new wife, Rei. Atsushi's desires escalate with each passing day, and finally they end up with an unusual relationship where they leave and have sex in just two seconds. Although he realizes that everything will collapse once it is discovered, he learns the pleasure and thrills of having sex with Atsushi, who is stronger than his father, and is unable to get away...