The Toy Box (1971)

When Ralph persuades his girlfriend, Donna, to participate in a bizarre party, she discovers the guests are to perform erotic plays in the presence of a corpse - Ralph's millionaire uncle. The players are promised gifts from the "toy box." Ralph and Donna await their turn, when the mansion's doors lock at midnight; and it's not long before they discover the players are being murdered by... the dead uncle?The Toy Box was on the Section 3 Nasties List and were liable for seizure and forfeiture by the police. No UK re-release.