Story:You caught a very thicc Raichu and it turned out the Raichu you caught was gay. Your not gay but the Raichu was so thicc you could not resist and thought to yourself "Well I will be able to reach its max happiness level easily so It can survive more KO's without fainting might as well sooooo thicc." So you fucked and had a good time and became bisexual for pokemon but remained straight for humans.