[Hayashida Toranosuke] Thanks for the meal, Big Brother (Nyotaika Ryoujoku!! II) [Soba]

Big brother Hibiki scores a book promising '100 Ways to Absolutely Get a Girlfriend' and decides to demo it on his two younger brothers—until a sudden transformation leaves him with a soft, bountiful body crowned with big breasts that Yuuki and Hazuki can't keep their hands off. Squirming protests melt into breathless moans as the pair takes turns 'studying' every curve of their transformed sibling, finishing deep inside before one eagerly demands a turn at her pussy. The closing punchline lands sweet: with both little brothers thoroughly educated, only big brother remains a virgin—and they intend to keep learning a whole lot more from that lush new body.