Health & Safety Guide

Latest Update: May 2024

Physiology

A good book on the basic physiology of the anus, rectum and lower intestines is the book Anal Pleasure and Your Health by Jack Morin, PhD.  Knowing just what is up there and then going in yourself with fingers to see just how everything is placed is essential to playing with the least amount of risk for injury. It is a great resource for those starting out in the discovery of their hole and understanding others’.

The Anal Sphincters | First Ring

What most people don’t realize when starting out, is that there are actually two sets of anal sphincters composed of separate rings of muscle, one is called the external, the other internal. You can actually feel them both with your finger if you know they are there, with the outer one open the inner one feels like a wide flat band when closed.  Together they are commonly referred to as the First Ring.

The external one is the one you can loosen or tighten at will, the internal one, along with the Second and Third Rings, are part of the autonomous nervous system and the reason why your hole stays closed even when you’re not focused on it. This internal sphincter requires practice to learn to control and allow it to open for larger objects.

The anal sphincters are not primarily responsible for helping maintain continence. The urban legend believed by many not into butt play of people having to eventually wear diapers is not founded in any fact. Playing with your hole and stretching it will NOT make you incontinent. Damaging the Pubo-Rectalis or Rectal-Sigmoid Junction deeper inside can.

The section of colon immediately inside the sphincter is called the Rectum. It will absorb any last bits of moisture from feces, so it’s important to think about what kind of toys, chemicals and lubes you put up there, since it will likely find its way immediately into your bloodstream.

Second Ring | Pubo-Rectalis | Pubo-Rectal Sling and the Rectum

Although you can have feces in your Rectum, the bulk of it is usually held back in the Sigmoid or if it passes that, then by the Second Ring, which is a loop of muscle attached to the pubic bone at both ends and embedded within a whole sheet of muscles within the cavity of the pelvis. In the resting state the Second Ring keeps the rectum pulled up and forward to create a sharp bend, pinching it off.  As part of a bowel movement, this muscle relaxes and allows the rectum to straighten out to let things easily pass.  This is why learning to relax this ring is helpful in the enjoyment of anal sex. I can personally attest that penetrating it can even deliver feelings like a second anus would when manipulated in a particular way, so seeking out a large endowment or playing with longer toys is not purely a visual fetish, but has a real basis in physiology for those seeking that type of pleasure.

To further this point, on those occasions when I take a fist past this point, or when I play with certain toys deep, during the withdrawal it can feel as though the hand or toy comes out of me twice. The first time it surprised me, as I wasn’t watching the action down below and at one point I had thought that my partner had completely pulled their hand out of me. When I realized he was still pulling I looked down and saw he was still in past the wrist. It was the Second Ring that had produced those feelings in me. I can replicate this same sensation on myself with toys.

When people complain of a pain inside during anal sex or playing with toys it is most likely the Pubo-Rectalis that has not relaxed or is in a position to create a blocked rectum. Sometimes I have felt a snapping feeling inside like a rubber band, which I have attributed to this muscle.

Since they are both on the autonomous nervous system the pubo-rectalis and the internal sphincter, respond to and store up stress, so it makes sense that uptight people have rightly earned the designation ‘anal-retentive’. But through focused relaxation one can learn to control these muscles and relax them at will. So it goes a long way to say that peace of mind and good relaxation techniques are as essential to a happy hole and productive playtime as anything else.

Third Ring | Rectal-Sigmoid Junction | RSJ and the Sigmoid

Once past the Second Ring, the next gateway encountered is the entrance to the Sigmoid. It can vary in distance between 6 ½” and 12” with individual variation either way (Alazmani, 2016). Recent studies on the Third Ring have shown strong evidence for a sphincter at this junction rather than a simple narrowing or bend (Shafik, 1999)  which responds to opening it in such a way that it initiates the process of a bowel movement, called the rectosigmoid-rectal reflex.  Contractions in the Sigmoid and Rectum are triggered while simultaneously a relaxing of the Second Ring and internal anal sphincter occurs.