While some yogis practice abstinence as part of their yoga, many yogic lineages are tantric. Tantric principles acknowledge the body as divine, and integral part of your spirituality, and all bodily functions are acknowledged and respected, not hidden. Sex is a natural expression of love, and of energy, and there are many people in Western Society who have a variety of issues around sex. Generally, if people have a low sex drive or low sexual control, self-esteem is affected.
Yoga can help increase sexual vitality and control.
There is nothing wrong with sex - it is healthy, and can be physically satisfying, fun, and transformational if used to attain different levels of consciousness. A healthy, active sex life can make your body healthier, your mind happier and more clear, and your interactions with others more joyous. I feel that there is no shame in our bodies - and the first step towards a healthy sex life is to love your own body, and be comfortable with your entire body. Find a partner who you can trust and understands this, and explore each other's bodies - if you are shy about having your partner touch part of your body, for example, the anus, then practice touching there, in a safe and loving setting, using massage and softness to help each other accept the body in its entirety. Second step - open mind.