Seeking Help find manga with trap?

Apr 2, 2018
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In this manga, an old guy turns a guy into a girl for himself, so to speak. It makes him love sex with men. He resists at first but then becomes a pervert. There's even a gangbang moment, but that's just this femboy fantasy.
he pretty young i think. With short hair. I don't remember exactly whether it was an old man or a guy with glasses