Reform School Girls by Andrew Shaw

'depraved wantons trapped by a wall of sin!'

From the back:

Sin walls muffled the lustful sounds of the wanton girls it sheltered. Take one of them - any one. A girl who broke the law and was sentenced to the reform school Sentenced to pay for her evil ways and learn new and worse ones. Put her behind the walls, bottle her up and turn the guards and lesbos loos on her. She'll pay for her sins - while she plays the evil game of lust they demand of her. And then finally she may find a way to escape, to break from the lust life forced upon her, only to find that it is too late, she is now one of the lust damned!