Aneki... My Sweet Elder Sister: The Animation

Season 1

A young student has a strong attraction to his stepsister so he constantly keeps looking at her, but she always seems to despite him, so he finds a relief in his 2 swiming class teachers, he like one the most and he always idolizes her not knowing that she is in fact as lewd or even more that himself, so when the teachers discover his stalking habit decide to punish him in some ways he never expected. After that finally he gets to know that his sister in fact feels the same for him so they decide to be honest with their mutual love.