Lady Steffi wanted to punish this loser for always being a nuisance. She did not want him to be a nuisance any longer so she turned him into a human horse and she had him carry her on his shoulders for a long time until he could not do it any longer. Lady Steffi got what she wanted as the guy learned his lesson and never became a nuisance to her any longer.
This mistress is petty and when someone does anything as small as even looking at her and she interprets it as being looked at in a funny manner, she gets pissed and she can torture that person badly. That is what she did to this guy for looking at her in a way she perceived to be funny. She then used her boots to torture him by riding him like a horse and stomping on him.
This guy was not cooperating with this mistress and she was pissed at him. She did not want to allow him to mess her up so she tortured him cruelly. The mistress could not think of a better way to punish him than to use her riding boots. She used her riding boots to inflict pain on him and she even rode him like a human pony. He cooperated with her after that.