Futago no Haha Seihonnou
English title: Menage a Twins
Japanese title: 双子(フタゴ)ノ母(ハハ)性本能
Alternative titles: Futago no Bosei Honno
Type: OVA
Source: Visual novel
Episodes: 2
Status: Finished Airing
Aired: May 25, 2005 to Aug 25, 2005
Duration: 30 min per ep
Rating: Rx - Hentai
Studios: Dream Entertainment
Producers: Milky Animation Label, MS Pictures
Licensors: Kitty Media
Genres: Hentai

One day, Minoru received an e-mail sending to the wrong address. It was the first accident. It was sent by a woman named Akane. Somehow, he felt as if he knew her, but he couldn't understand why he felt so. The next accident happened. When he and Tomoe went home after shopping, they happened to see Akane. Looking at Akane, Tomoe put on a grave face. Putting him between them, they looked at each other. Their encounter is just an accident or intentional? Being disclosed their relations, Minori lost his calmness, and couldn't help devouring their sexual bodies. 

(Source: AnimeNfo)