The fantasy of being bound comes true here! Tactile feeing of restraint, feeling of helplessness for its own sake, feeling of total Mistress' power and control under them make these slaves to wait with impatience for the next Mistress' step, for Her next word. Each touch, slap, word, breathe of Hers becomes so valuable for them as the whole world becomes so small where just a slave and Mistress are!