Fault!! Service: Aratanaru Rival
Japanese title: フォルト!!S(サービス)~新たなる恋敵(ライバル)~
Type: OVA
Episodes: 1
Source: Visual novel
Genres: Hentai
Studios: T-Rex
Producers: Cotton Doll, Lune-Pictures
Duration: 26 min
Rating: Rx - Hentai

After a tumultuous summer vacation, Shuuichi begins the second school term while under the constant love assault from Ai and Mio. One day the tennis club leader Reiko announced that they will participate in the school festival at the end of the month, which they decided to run a cosplay cafe after much wrangling. Afterwards, she decided that she wanted to run as a candidate for next term's student council. That wasn’t the end of his tumultuous days as a transfer student suddenly appeared in his class...

(Source: AniDB)