Island of Death (1976)

Island of Death (1976) is a Greek explotation/horror film about a psychotic, religious couple who go on a violent killing spree in a small Greek island. Christopher (Robert Behling) and Celia (Jane Lyle) are a British pair posing as newlyweds but are actually brother and sister in an incestuous relationship. They arrive on the isle killing anyone they deem to be preverts and/or sinners.

It's a pretty sick film with the uncensored version having been banned as a "video nasty" in the UK for 35 years. An uncut version was finally released in 2011 and features a nude Behling in a few scenes. He's raped from behind by a guy who exposes his pair butt and shows his behind again (along wtih his testicles) in a scene where he pees on a woman.