Granny Gets Double Teamed

In this Japanese anime, Pantera, a young girl named Yui is taken captive by a group of perverted monsters. They strip her naked and tie her up, then proceed to sexually torture her in the most depraved ways imaginable. As Yui struggles to escape her bonds, she discovers that the monsters are not the only ones watching her suffering - an audience of twisted onlookers has gathered to enjoy the show. But even as Yui despairs, she finds herself growing more and more aroused by the pain and humiliation heaped upon her...