Tantra treats sexual energy as an ally, rather than something to be suppressed or discussed behind closed doors. It does not deny sex, just the opposite in fact; it embraces sex. Tantra is the only spiritual path that states that sex is sacred and not a sin.
There is a most beautiful word for sex in the Sanskrit language, and that is Kama, which means sex and love go together; they're undivided and indivisible. Most everyone is familiar with the classic Kama Sutra, the 7th century Tantric scripture.
The essence of Tantra is the full expression of existence; a merging with, rather than a withdrawing from sexual energy. This energy is used as ignition for firing the body's biological energy system, merging it (and you) with universal energy.
In Tantra, sex is used as the cosmic union of opposites, to create the polarity charge that connects with the primordial energy from which everything arises in the universe... the totality of All.