Now updated for volumes three and four.
In terms of ecchi manga that are read purely for the fanservice, To Love-Ru and Asa Made Jugyo Chu are the cream of the crop. Similar to To Love-Ru, the original writer brought in a hired gun to do the art work, and in both cases it is the art that steals the show.
Asa Made Jugyo Chu! (4 volumes, complete?)
The artwork in this series was handled by Munyu, who’s best known for his work on the Ladies versus Butlers adaptations, including the anime. He’s also done his fair share of hentai works.
The title of this manga in English is “See Me After Class!” If you’ve seen the OVA then you know the story. An effeminate male and future trap character is taken under the wing of a busty teacher and in no less than 10 chapters or so he’s surrounded by a harem of mostly large breasted women. Of course, several of the harem participants fail to make the OVA- of particular note is the ultra busty blonde class president, Patricia Benpouin.