Okay so the only scene I remember is there’s 3 ppl. 1 older guy driving the car, and a young girl and guy who are just friends. They pull over to camp out. The older guy leaves for some reason. Previously to this, the young guy can’t get a hard on. So on the camp site, as a joke (I think) they see a group of girls that are willing to help. After this (which I don’t think they go through with that) it starts raining. The young guy and girl go into this tunnel thing and he ends up getting it up.
So I feel like this movie is 2005-2015. I watched it on either Netflix or HBO on demand. I feel like the actors are pretty famous but for the life of me can’t picture their faces.