If it's the same woman from the beginning of the story then she's Geonyeong's former "lover" but not really lover more like friends with benefits. He would just call her up to have sex before games. This was all before he met Wonwoo though.
SPOILER DON'T READ AFTER THIS IF YOU DON'T WANT SPOILERS
So judging by the raws it seems like nothing happened between them that night though.
his ex :(
That better be the case.. if they banged i’m gonna go feral.
oh my holy fuck! I'm dropping this if they had sex the day he promised to take him to the beach!!!!!! THAT BITCH IS SO FUCKING ANNOYING
OMYGOSH! DID THEY DO IT? THE DAY HE PROMISED TO TAKE THE UKE TO THE BEACH? HE HAD SEX INSTEAD OF TAKING THE UKE TO THE BEACH?
SPOILER.....
No nothing happened between them
Can someone spoil me .? Who the hell is that Red haired bitch? Omyghad my temper is rising