One of the best known sex comedies. The setting is a sex clinic in Japan. The plotline revolves around the quirky (and perpetually horny) Doctor Sawaru Ogenki and his beautiful nurse, the busty Ruko Tatase, who help patients through their problems, and the cure almost always involves sex.
The manga is hilarious and completely exaggerated (as are the body proportions in it). The patients suffer from bizarre sexual problems and our doctor and nurse are more than willing to cure them from their problem. Slapstick galore. Do not search for refined humor here.
Although focusing about sex in nature including heavy kink play, it can also fall under the category of comedy instead of just adult hentai. If one can get past the very mature attitude those might also find it humorous how the doctors wish to cure patients, as well as some of the abstract images involved in said cure. Referring to sexual intercourse as a game of pinball, or the male anatomy as an actual missile (or gun) are just some of the examples involved.