Dokkiri Doctor

(from ebookjapan):

Dr. Haruka Nishikikoji, the director of the Shirobara Clinic, is also the school doctor at Nanasei Junior High School, located right next door. So students come and go, just like in the infirmary. And one more. Miyuki, the nurse. She is firm, and in addition, cute and sexy. But for some reason, she is Haruka-sensei's fiancée. But the two are still in a platonic relationship.

Now comes the first volume of the exploits of Haruka-sensei, a naughty and dirty...genius, eccentric, or rare inventor...who is not known at all!