The pubococcygeus (PC) muscles control urine flow and hold pelvic organs in place, but they're also the muscles that contract during climax.
The intrepid participants start by inserting a jade egg tied to a light pouch full of crystals, and proceed to swing the pouches between their legs while clenching
their pubococcygeus (aka the muscle you use to stop peeing).
When you orgasm, a special area of your pelvic floor called
the the pubococcygeus (PC) muscles contracts, leading to that big moment.
With guidance from a health professional, she will retrain the pelvic floor muscles — particularly
the pubococcygeus muscles — to appropriately respond to penetration through a series of physiotherapy - like exercises focusing on pelvic floor muscles.
These muscles include the sphincter muscles, the urogenital triangle, and the levator ani (which is made up of
the pubococcygeus, illiococcygeus, and puborectalis muscles).
The exercises are designed to strengthen
the pubococcygeus muscles, and consists of contracting and relaxing the muscles which form part of the pelvic floor (sometimes called the «Kegel muscles»).
The Kegel exercise described by Dr. Kegel was a contraction that was not excessive and isolated to just
the pubococcygeus muscle while avoiding the use of gluteals, abdominals, or muscles in the mid-back region.
You can see that the erector spinae muscles draw the sacrum into flexion (nutation) and the muscles of the pelvic floor (especially
the pubococcygeus) draw the bone into extension (counternutation).
The levator ani muscle group is made up of
the pubococcygeus muscle, the illiococcygeus muscle, and the puborectalis muscles.