Good stories, This is bk12 of the Toudou Group series. In this book you have Chiharu×Kazuki + Jin×Jun again, Kaoru Kirishima makes an appearance in this one too.
Prequel ~ bk1 Happy Yarou Wedding - bk11 Ueta Aikata
Sequel ~ Torawareta Aimai Kemonotachi
Amaeta Kemono no Shitsukekata