Saw this article from the New York Post, a tabloid. It seems some people find being bound rather relaxing. I could guess it might be the adrenaline and endorphin rush. Maybe someday this could be as mainstream as yoga is today,
What say you?
Play safe! T.T.
http://nypost.com/2016/06/15/bondage-helps-me-relax/
PS- I should add that these classes are most likely limited to those over 18.