The brother gets extremely excited seeing his sister's panties exposed without a care in the kotatsu. When she falls asleep, he sneaks into the kotatsu, teasing her sensitive area that's all sweaty from the heat. Just as he's getting absorbed in the mischief, she wakes up, and instead of getting angry, she provocatively touches his penis with her foot. The brother gets into the mood and they have sex right there, holding back their voices so no one else finds out. He cums inside her thoroughly, enjoying the sensation.
