
i've aleady forgot the details, wait so he's still a virgin? i thought they already had sex

Hes a virgin in the literal sense that hes never penetrated before - for some reason they differentiate between that and being on the receiving end (which is just stupid imo, theres no way Kokusai can be considered any kind of a virgin anymore after all theyve done).
Chiga basc thinks Kokusai wants to know what it feels like to put it in someone, which is why he offers up his own ass

Can someone explain this chapter? Im lost, what will happen if he won?

page 4 and 5 are out of order. page 5 should be before page 4.
this is my impression of the events in the extra:
in the first RPS with yuri and the other guy i don't remember the name of, winning would mean the guy gets the toy up his butt and he doesn't want that. in the second RPS, winning meant getting the bread of his choice, but because of the trauma of what winning meant from the first round he freaks out for a second until he realizes the stakes and people he's playing with are not the same (which is why he says "wait...i haven't been touched"). the other two at the end were blushing and repeating the events ("the winner was takashi") because they both are in love with him and he looked really happy when he shouted he won first choice which was cute to them.
hope this helps!
where can i read the raws?!?!