As a recovering scientist I come across some interesting articles from time to time.  

It's just the abstract but happy light reading.

"Consensual BDSM Facilitates Role-Specific Altered States of Consciousness: A Preliminary Study"
 Ambler et al., Psychology of Consciousness: Theory, Research, and Practice, Sep 22 , 2016

http://psycnet.apa.org/psycinfo/2016-45384-001/

Hope there's lots of pictures.

I still have access to my former employer's electronic library. Found and read the entire article. Someone at Northern Illinois University’s Institutional Review Board has courage. Most universities would not allow this type of research to be conducted under the university's name. I support this type of research, but my experience (having sat on an IRB) is that getting any kind of sexually-related research approved by an IRB is very difficult