Maokin: Joshikou Kyoushi no Ore no Kintama ni Maou ga Yadotta Ken

The Demon Lord has hidden itself in the testicles of Nakata, a male teacher at an all-girls school! If he ejaculates, the Demon Lord will be unleashed and the world will be destroyed… Furthermore, the girls at the school are being controlled by magic to try to seduce Nakata…? With the fate of the world on his shoulders, will Nakata be able to withstand the temptation?

(Source: Yanmaga, translated)