Motto Teikou shite Kure yo: Sawayaka Ouji no Yuganda Seiheki

Okumura is just another regular playboy who dislikes Karasawa, who's more popular & has better grades. Until one day, Okumura hears from his friend that Karasawa has erectile dysfunction. Okumura tries to oppress Karasawa because of his supposed ED.

(Source: Shusuisha, translated)