18+ Akumade Majo no Yuuwaku desu kara

Akito Shiraishi, who lost his parents when he was young, graduated high school and has been looking for a job. After a succession of failures, Akito finally gets hired as a janitor at a certain school. However, it somehow turns out to be a school for witches in another world! Furthermore, he has been tasked with doing a certain something to the girls...!?

(Source: Takeshobo, translated)