B is for Binding. :)
I'm not really much into BDSM and seeing pictures of women (or men) tied up really isn't my thing.
Except when it comes to my nipples.
There are times when they are just so aroused that I just can't help but tie those little babies up.
For some reason, my nipples prefer this attention mostly during masturbation. In fact, my self-induced orgasms often require at least a some nipple play.