"You have to wash it properly!" My sister came into the bathroom and pulled back the foreskin of my foreskin and washed it. No matter how much we're brother and sister, if I'm stimulated so directly, I'll get an erection. Then my sister's eyes, which were full of love just a moment ago, changed to the erotic gaze of a lewd woman... The bathroom suddenly became erotic! Although we knew it was wrong, we were dominated by the lewd atmosphere and did some naughty things on the spot, and then we went back to the room and had full-fledged sex!