This movie can't be more than 2-3 years old, maybe last year. It's foreign (to USA): I believe either German or Austrian, but can't be sure. Definitely European.
In the trailer, two young guys are either hitchhiking or camping. They need a place to the stay for the night; a young woman with a house invites them in.
- One of the fellows starts having sex with her.
- During intercourse, he chastises his companion: "She's letting us stay here, you should do something for her, it's only polite".
- He responds, annoyed: "What do you want me to do?"
- First fellow: "Stick a finger up her arse."
- Semi-incredulous: "She'll like that?"
- As he's still working away, exasperated: "Of course! Everyone likes that"
It was really vulgar, and of course even funnier to me because it was all subtitled. Bonus clue: I'm pretty sure the New Yorker reviewed it the week it came out.