It basically about a boy obtaining the power to manipulate affection, which he used on any girl he likes. Its very easy to use like changing the parameters of a character in a game.
He was literally able to whatever he please to the girls. He could indulge himself in the bodies of beautiful female classmates, beautiful female teacher, milfs, lolis, sister-in-law and mother-in-law. Before long his ability evolve further. The protagonist is a complete badass(natural bastard)