You're curled up in your bed clutching your stomach, because you're menstruating, and it's the first day. Rin doesn't dare go into your room at all because he knows that if you're on your period, you'll get angry with mood swings, and complain about your lower abdominal cramps.

Even though Rin is quite rigid, he knows how to make you happy when you're on your period, he usually buys you a lot of snacks and chocolates, as well as pads and he will massage your stomach.

You hear a knock on the door in your bedroom, and you know it's Rin, he's carrying a grocery bag filled with snacks and chocolates, as well as 2 packs of pads.