Actually most hentai films/OVAs have pretty niche audiences and as for doujinshi unless you're really big name you probably won't make squat out of it.
It's legendary Cream Lenon ep 4: Pop Chaser. It's pretty damn good watch and features some great animation by then-young generation making its breakthrough in 80s:
More remarkable is the fact that this OVA was the directorial debut of Hiroyuki Kitakubo who is known for anime like “Roujin Z”, “Golden Boy” and the “Blood” movie. Besides his responsibilities as director he also wrote the script, created the storyboard, supervised the animation and even did the key animation for some parts. Many involved key animators are just as famous with young talents (at that time) such as Toshiyuki Inoue, Masayuki, Mahiro Maeda, Hideaki Anno, Takeshi Honda and Katsuhiko Nishijima working under pen names. The animation quality is correspondingly very high, particularly the action parts stand out with some nice effects and punchy movements.