Oh god. As much as I'm torn between incest material, this episode was just win
Leave it up to SHAFT to make tooth brushing such an erotic act. When Karen said "Iiyo" I was like, "Kittaaaaaa." Of course they were interrupted, but they ended up continuing anyway after she left?! I don't care about their relationship anymore, I just want moar!!
Araragi seems to think Tsubasa > Karen > Hitahi now anyhow