Sis

it said shes bi, so ill keep her company ;)

No, i think the seme(the blonde dude) imagined what he would do with the black haired dude, to show us that he isn't like what he seems. I think it's just after he came back from the phone call, when they're both asleep on the table, so they didn't go fuck, it was all a "what if", at least i think

wow, it's an interesting theory! (╯°Д °)╯╧╧ I have to re-read from this perspective

Haha, i like those stories where you can imagine what you want, with different interpretations!
I hope you'll like it that way, but honestly i thought it would be super mean if they left the uke's sister alone at night and wasted, so i prefered thinking they never left haha!

Completely untrue. Look at title. It was retrospection... It was shown that Herma was telling something when Wolf was drunk and at the end we came back to that scene. They fucked.
People you have to have everything chronologically to understand plot...

What they said is untrue.