There is a strong impact on the slave when he is faced with continued bondage of one kind or another.

The potency can be ever more increased when the slave is in effective bondage  and then kept in another layer of bondage and yet another, where each layer seems quite unnecessary.  It has a strong psychological impact.

One of my favourites was a box cage, this was like a wooden kennel/coffin that the guy could squat down in on all fours, he had a 2 inch hole to look out of, all that he could see were the bars of the prison Cells he was in. At the bottom was a slot for his dog dish. He was left in there for an extended period on time (some days), and he had to deal with his toilet problem the best he could.

The bars of the prison could also stop any possible rescue, he was in solitary for quite some time.