Apparently the same prank the uke by telling him that was a girl friend of the uke and that this friend changed her gender into a man but ofc not. It was just the cousin's friend.
It's kind of a mess the begining I had to read it twice because I could not get why the uke adress the seme as 's/he' all the time and thought it was a translator mistake or smth but not hahah well if i'm wrong pls tell me XDD
So, I didn't know there was a chap 0 and that explains a lot to me hahah XD
Seme pranked uke by telling him he was the uke's friend(a girl) and somehow that she turned into a boy but that obviously didn't happen, it was just the cousin of the uke's friend that wanted to bang the uke for a long time.
Omg, really! Well, thank you for clearing it up!
Wait, what just happened? Can someone explain, please, I don't get it.. I'm too stupid for this, okay xD