Hmmm... I checked the list of my models, and found out that only couple of them (total models number now is more than 25) does not have fun during our bondage photosessions. And also these couple models work with me only once (maximum twice). And it's not because I refuse them, but because they dislike this process...
Most part look at this process just as at new funny game.
Especially when two girls are good friends in real life and work together.
In such case the main problem usually is to find moments without silly smiles at least on "victim" face