He showed him what it would look and feel like dating another alpha. They both want to assert dominance, he did that to let Byul realize what he's really getting into
I've read it before, it's a manga they were a couple highschool? I think, they grew up Yada yada
They went to meet some friends seme wanted to go back home, uke went to bed pulled down his pants and said some Lines along "I still have what you gave me last night" refering to cum
Literally fucked his brains out
Bruh fr TT
Lowered his iq to the negatives