So, going back to find the door kissing scene, and there's no way there isn't a dude she's involved with. Chapter 2 had a torn condom wrapper, and Chapter 4 had her do the moans and say "cosplay sex" with someone else there.
At best, the "kiss" was her licking something like a lollypop, and that she shoots solo porn with a camera person. That feels like the angle the author is gonna go with; unless he finds pleasure in fucking with the readers and she's banging someone while teasing her little cousin.