This one's from Seieki Benjo Kotegawa Mihariyaku no Gyakushuu by Sorairo March (Narusawa Sora) which isn't tagged as defloration on nhentai.

I'm planning to make a deep learning model that can determine whether a doujinshi has defloration. I have around 500 defloration-positive pages which is far from enough for training, but I hope to get enough eventually.