Tantra is indulgence with awareness.

Tantra says whatsoever you are, the ultimate is not opposite to it. It is a growth; you can grow to be the ultimate. Tantra says accept yourself as you are. There is no opposition between you and reality. Do not create a gap between the world and the Nirvana. You are part of it, no struggle, no conflict, no opposition to nature is needed. You have to use nature; you have to use whatsoever you are to go beyond. Tantra is a science to achieve just that, it is not a philosophy. Tantra is not an intellectual proposition, it is an experience. And for this transcendence, use yourself.

Don’t fight the snake

For example, sex is there, the basic energy you are born through, born with. Tantra is a path where you use the energy of sex - also known as Kundalini for this transformation. Do not fight it, transform it. Do not think in terms of enmity, be friendly with it. It is not evil, it is not bad. Every energy is just natural. It can be used for you or against you. You can make a block of it, a barrier, or you can make it a step. 

Tantra says be aware of the desire; do not create any fight. Move in desire with full consciousness, and then you can transcend it. So Tantric alchemy says, be friendly with all energies that are given to you. Welcome them. Feel grateful that you have sexual desire. Feel grateful because these are the hidden sources, and they can be transformed, they can be opened. And when sex is transformed, it can become a creative force. So, Tantra says, indulge but be aware.