There are three sets of muscles, they act like a hammock/sling from the back to the front of your pubic bone, encircling the openings to the vagina and the rectum. when you orgasm, these muscles contract. The stronger they are, the more intense the sensation.
The classic exercise for these muscles, basically involves contracting and relaxing the muscles, as if you were trying to stop the flow of urine. The next time you’re in the bathroom, try and stop mid stream so you become familiar with these muscles.
Now you are familiar with these muscles, slowly contract your muscles, drawing inward and upward. You need to hold for three seconds then slowly relax for three seconds. Now repeat as many times as you can, gradually working up to 25 or 30 squeezes with the three second intervals. Try different positions, standing, sitting or laying down.
The uterus is hollow and a muscular organ, uterine contractions can enhance your orgasm, If you are able to control your uterine muscles, for example, to pull the uterus up during sex, exposing the very top of the vagina, to penile thrusting. This area is very sexually sensitive for women and its possible to almost instantly orgasm when this area is stimulated during sex.
To locate and identify your uterine muscles, lay down and lift your bottom and legs in the air. This bottoms-up pose allows your uterus to sit on top of your vagina. As you lay down, you may feel air moving out of your vagina. That is the sensation you want to re-create by tightening your lower abdominal muscles, which are right above the uterus. As you tighten these muscles, Think of it as if you are breathing in and out through your vagina. Contract and relax the muscle 10 times, once a day.