4000倍の男 (Series) favorite_border

[DeepL Translation - needs review] Volume 1 Introduction: Seigo Hasegawa, a high school boy with no sex drive, suddenly gains 4,000 times the cheat sex drive after a hard blow to the head one day. His childhood friend Anzu Yagami, a beautiful girl who hates men, reaches out to him to help him (sexually), but...? The runaway sexual desire is unstoppable!

(Translator: DeepL)