can anyone tell me why the top was puking after the kiss in the beginning phases

im curious about that too,,, it looks like he was initially grossed out by it and was doing it only for a reason and then finally fell starving for our mc but idk i could be wrong

Theory he once was dead/His Body ist modyfied so human fluids are Like poison. But until now all Just Theory. He Likes IT so nothing s gonna Stop him

I have the same theory too