I had sex with him 9 times and still never had it happen.
in regards to chibi drawings, I only managed to get half of them cuz no matter what I did, most of the time about 3 or 4 of the same ones would trigger again and again, sometimes twice in a row. It got really repetitive. Are there just specific combinations in foreplay that trigger the other ones? Or do you just need to have sex more times to unlock them?