Omiai Aite wa Oshiego, Tsuyoki na, Mondaiji was made by Seven and has a rating of 5.51My review of this one is fairly simple - It's hentai and not Romance, Ecchi, School, Josei!
It' s good. The story? Yeah there isn't any. A guy likes his teacher who is dating his brother. But he likes her so much he conquest her and BANG!