Teisou Gyakuten Sekai de Nariagari wo Mezashite Otoko Kishi ni Natta Boku wa, Yarimoku Onnatachi ni Karada wo Nerawaremakuru

The protagonist, who became so obsessed with being a military otaku that he became a soldier and died in combat, is lucky enough to successfully reincarnate in another world. Hoping to succeed as a military man once again in his second life, he becomes a knight, but the world he reincarnated into is a chastity-reversed world where men are sexually targeted...!? Armed with modern military knowledge and aiming to rise in this other world, what assails the protagonist are beautiful girls with all kinds of fetishes who are only after his body! Will he be able to grasp glory while fending them off...?

(Source: Mag Garden, translated))