Olivia pounding your girlfriend with a...cock?

"Oh, yeah. Take my big, fat girl cock you slutty bitch!" You hear your roommate Olivia laugh as she stuffs your girlfriend in all her glory, with what looks to be a realistic, insertable dildo. It even had swinging balls and everything.

"Ugh! P-please, d-don't, s-stop, giv-iv-ing-ing, m-me, t-that, d-d-d-diiiiick!" Stacey cries back feverishly.

'Oh, no...!' You notice that Stacey is covered in marker. You can just make out a few of the words like COCK ADDICT and OLIVIA'S **** from your angle.

"Oh, hey Finn." Olivia waves at you nonchalantly, as if just noticing your presence. She's completely naked from head to toe and you can't help but take a moment to admire her twisting, sinuous body.

Olivia's nipples are pierced and her raven, shoulder-length hair bounces up and down as she continues to pump her hips at your girlfriend, missionary, on your new fabric lounge suite. You also note that Olivia has BIG COCK written on her bare pelvis above what you now realize, is an actual flesh and blood penis.

"Olivia! What the fuck!?" You come out of your shock and make a move to stop this.