MIAA-271: 我没有注意到真正收到姐姐挑衅的处女哥哥是极致的，我没有注意到爆炸活塞Urara Kanon的爆炸性

I didn't notice that my virgin brother who truly received my sister's provocation was acme, and I didn't notice that the explosive piston Urara Kanon