Densetsu no Yarichin VS Teppeki no Shiriana

Overview

Hachiten High School, also known as Hatenkou, has two of the "strongest" students in the world. Mikagura Iori, a legendary playboy who has sex with different women 365 days a year, and Sena Minami, an iron-walled butt hole who always assaults back any guy who approaches him for his behind. Which is stronger, the strongest spear or the strongest shield? Mikagura and Sena decide to settle the matter in a sex battle. But as they face each other, they begin to develop feelings...? "I never thought I could get heated over a man." "Perhaps...Is this love?" The pure romantic comedy of the two who have never been in love, though their lower body level is at the highest level! (Source: Libre, translated) Note: Includes five extra chapters.

Source: AniList