A young man and a girl went out for a walk in the forest

A young man and a girl went out for a walk in the forest in their caravan. They met a family consisting of a child who wears a mask and covers her face. She has a brother and two sisters. They scared the young man from his girlfriend and tied his girlfriend in the caravan and took turns raping the young man.
At the end of the movie they were preparing the young man until their mother came and had sex with him while he was tied to the bed and she was holding her hand gun until he finished and she killed him, but his girlfriend had untied herself and came to save him.
The young man’s girlfriend had a severed arm.

what year did you see it? was it american? it had nudity? you would say it is horror?