I watched Kiss X Sis, I don't think I ever finished it though because I can't remember how it ends.
It made me and my penis giggle, especally in the bath scene where the 3 of them fell over each other, wound up in a dirty position and he unintentionally pleasured them with his mouth and hand. It's the same reason why it made me jealous. Where's my harem?!
Edit: Yeah I did finish it. Wiki'd the episodes.