Musuko no Tomodachi ni Okasarete
English name: The Cougar Trap
Genres: Hentai
Type: OVA, Episodes: 2
Aired: Mar 13, 2009 to Jun 12, 2009
Studio: Y.O.U.C
Source: Visual novel
Rating: Rx - Hentai
Synopsis:
Yoko is happy. She lives a peaceful life with her husband, Masahiko, and their son, Kazushi. But there is one thing she complains... They haven't had sex for a long time. One day, a friend of Kazushi comes to her house. His name is Ryouto. He is handsome and polite. But she doesn't know yet that Ryouto has a secret personality... 

(Source: AniDB)