To explore more about Earth culture I'm guessing
That was an extra before they dated
But if that was so they wouldn't have been making out or have sex.
Rereading it I think it was before they started dating and confessed their feelings but at the point they already started having sex. Cuz like the MC said that he was his childhood friend and that they don’t get along in the extra but once they confessed and everything they obviously ended up getting along and became a couple. So I think maybe it was like right after they first started hooking up
And to go off of what I said I mean technically they didn’t show them having sex after the first chapter until the last one but that doesn’t mean it didn’t happen… that or I’m just delulu
Yo why’s the seme still meeting up with girls even tho he has ryuga