Lady Steffi was mad at her slave. And whenever she's mad, she likes to get brutal. She kicked him hard in the balls and put him in extreme pain
When Lady Steffi decided to work out, she started walking. At the end of her walks, she met her slave. She saw him as a way to treat herself. She has her slave open his legs so that she has a clear shot to his cock and balls with her feet. She wants him to feel all the pain she does as she is walking and getting into better shape. Kicking him in his tiny cock and balls is hard work but when he walks away sore, she knows her efforts are worth it.