>>212553730May as well fuck the girl and do Robin a favour.
If it's not you, it's going to be a random hobo whenever she feels like it, and they won't have the decency or the balls to tell Robin.
Just fuck her as as hard as you can, go to Robin, and say "Your alien gf is offering free sex to whoever is available lad, I'm sorry. I took a bullet so you wouldn't have to hear it from someone else."