Hmmm... I looked up an old movie:
Mark of the Devil, which I was sure had a rape it in it, but the info said no it didn't...
Next one I do remember clearly.
Cross of Iron is a story about German soldiers caught behind Russian lines during WW II. In one scene the men are having fun with some captured Russian women in a barn and one German soldier decides he will mouth rape his woman. She bit his dick off....