Mistress Dana was out to have fun with this guy and she made him wear a chastity device. He did not know what it was and he assumed that it was for them to have a lot of fun together. But he regretted it when she teased him while he wore it and his dick hurt as it could not grow bigger since it was constrained in the cock cage.
Mistress Dana wanted to dominate her boyfriend and she did it with her chastity device. She felt that the best way to deal with him was to trample and humiliate him and she did not hesitate to do it. He was shocked by what she did but she did not care about what he thought of what she did to him. As long as he learned his lesson, she was fine.