What if Butcher Vanity Xi Yi did Ego Renegade Boy Len's top surgery
Think about it
Boobs, while not entirely made of it, have fat in their internal makings. Fat, as we know, is a major component of cooking and is typically considered luxurious.
Assuming that Xi Yi isn't consistently rawdogging everything she cannibalizes, she is going to cook some of the body parts of her victims. And we know from the song itself that she doesn't want to waste anything from those victims' bodies.
So, hypothetically, since ERB!Len seems to be transitioning in a likely botched and/or outright illegal manner due to the lack of support he has.. would it not track for a cannibal to possibly want some willingly discarded titties?
Therefore, Xi Yi did Len's top surgery.