My beloved little sister, who I still thought was a virgin, was being used as a creampie toy for all of my friends.

Ichika, the younger sister who was born when her parents remarried when she was little, loved me and was attached to me. Ichika has a friendly personality and is good with my friends, which made me laugh, but I can't believe she was playing naughty games without my knowledge! My cute little sister! They still stoked the fact that my sister was unconscious about sex! "Let's do it too, big brother," my sister said to me, and something in my emotions changed...