I was slut to death by my older brother's ex-girlfriend

Tsukasa, my older brother's ex-girlfriend, suddenly appears. It seems that the terrible older brother who plays with women has sex trained him, even stolen him, and even dumped him, and I end up taking over him. There was no way I could pay back the money, so I was taken to the hotel and was stripped naked and sexually trained as my brother did to Tsukasa. Although I had refused to do so, the lewd perverted play I had never experienced before gradually absorbed into my body, and only Tsukasa could get an erection...