The series 'Dokidoki Oyako Lesson' follows the sexual education of a young man named Tatsuya at the hands of his stunningly beautiful and voluptuous stepmother, Aya, and her equally busty and seductive best friend, Ruriko. What begins as seemingly innocent private tutoring sessions to help Tatsuya with his studies quickly spirals into a whirlwind of incestuous and debaucherous exploration. Aya and Ruriko use the lessons as a pretext to teach him about carnal pleasures, their bodies becoming his textbooks. They initiate him with tantalizing teases, letting his hands wander over their massive tits and asses. Soon, the lessons escalate into hardcore fucking sessions. Tatsuya finds himself sandwiched between the two insatiable women, taking turns fucking their wet pussies and getting his cock sucked raw. The entire series arc is a progression of his sexual awakening, culminating in wild, semen-soaked threesomes where he learns to satisfy both women, filling them up with his hot cum until they are begging for more.