This was a rather... uncomfortable read, but here's the summary anyways.
The lion's customer made a bunch of loans, and was unable to pay them off, so he fled, leaving no ways to contact him. As punishment, the lion's arms and legs were amputated, preventing HIS escape. Now he will have to be used as a sex object until the debts are all paid. Visually you could tell that pain turned to pleasure by the end.
Few minor details I didn't know where to fit in, the lion was used because he was the guarantor, and the dog teases that after the debts are all paid, he'll be kept as his pet. Pretty fucked if you ask me.