**Answered** Looking for a BL manga I can't remember the name of

It was a yaoi manga and I'll try to give it a summary from what I can remember -
So a man randomly shows up to the main character's home saying he was his past classmate (who was a girl) but turned into a man because of a "sickness" or "disease." It turns out that he was just pretending and that the sickness wasn't real, he was just trying to get into the main character's pants by pretending to be his sister (who was the main character's past classmate)

I can't remember the title and I read it a year or so ago. Could someone please help me find the title? I'm sure I read it on this site.