Shinozaki-kun no Mente Jijou

Shinozaki, an ordinary office worker recently worried about being "off his head", is approached by a woman named Yuyake. She explains that her magician grandmother modified his body in the past...causing him to have a lot of inside machinery?! He'll have to receive internal maintenance from Yuyake...

A slightly wobbly magical remodelling life between a very ordinary salaryman, Shinozaki, and an enigmatic magician, Yuyake, begins.

raws:
https://comic.pixiv.net/works/4252