The Yoni egg. A physical aspect of tantra is the contraction of the PC muscle -in full the pubococcygeus muscle-. This is the muscle you tighten when you have to hold your pee. The PC muscle is a magic tool for both men and women when working with sexual energy. Strengthening the PC muscle is the same as with anything: lots of practice. This can actually be done anytime and anywhere: no one will notice if you rhythmically contract your PC muscle during a meeting, in the car, on a bicycle or walking in a museum. For women there is an extra powerful tool: the egg. Look for a semi-precious stone practice egg, such as rose quartz. First hold the egg below your navel to feel whether the stone feels good to you, because you will use it in your most receptive emotional area and the energetic charge of the stone always works on your energy system. Strength with resistance Bring the egg into your yoni and now practice, preferably standing, in contracting your PC muscle. You will find that you can exert more force now that there is resistance. Same principle: you can make a firmer fist with an object in your hand than with an empty hand. You may feel some muscle soreness in the beginning, as with any muscle that needs to be strengthened. Clean thoroughly after use and allow the drill hole to dry before reuse. The Yoni eggs are available in Jade, Rock Crystal, Sodalite, Jasper, Rose Quartz, Picasso Jasper, Aventurine and Red Jasper.