I have been asked the following question consistently by westerners.
“In the west Tantra is viewed as some kind of exotic erotic engagement between a couple and also exotic erotic massages. But what is the actual understanding in India?”

I am aware that tantra in the west is associated with exotic errotic form of engagement and massages.
Just as yoga has become a much distorted version of itself, outside India, similarly the understanding of tantra is also highly distorted.

Tantra is a practice of strict discipline, with an objective to expansion of consciousness.
It has two approaches, a right path and a left path.

The right path of tantra is the more popular form and is practiced in most households in India, as puja done at their home altars.
It involves engaging the senses through various offerings to a chosen deity. Oil or ghee lamp, incense, water, food, ringing of bell and blowing of conch, being part and parcel of the connect with the deity.
Mantra chanting and other ceremonies are part of this process too.

Then there are multifarious practices under Kundalini yoga, from meditation on chakras to other yogic practices, aimed at self realisation through facilitating ascent of Kundalini (the coiled up spiritual potential) to merge with supreme consciousness. These are also called Tantra.

In the left path of tantra, there is varying levels of engagement between a couple, at satvik, rajisk or tamsik way, under a guru’s advice.

A guru to emphasize is not just someone who has mastered a yogic technique or tantra technique, but who has seen the culmination of his practices and reached the highest consciousness. http://www.shuklacharya.com/uncategorized/guru/

For this only those people are selected by the guru, who have undergone strict discipline and have full control of their senses and conquered the lust within.

The beautiful idea behind it is that instead of worshipping a statue of a deity, a couple can worship each other as Shiv and Shakti manifest and invoke the Shiv and Shakti in each other.

If there is a sexual engagement in the couple, it is not sexual activity as commonly known, but a motionless coitus, resulting from each participant offering totally of themselves to the other, taking such an engagement as means to remain in a meditative state and become one with the invoked highest consciousness.

The confusion of mistaking this intense strict discipline spiritual practice to some exotic erotic engagement/ massage, stems from presuming Kama Sutra or Kama Shastra instructions to be one and sane as tantra.

Kama Sutra / Shastra is considered a scripture and its author venerated as a rishi. Rishi Vatsyayan. It is essentially a manual for householders and to be householders. Some of its verses recited as part of a Hindu Vedic wedding ceremony as well.

Kama Sutra/ Shastra deals with art of dating, courtship, marital responsibilities as well as love making techniques. Rishi Vatsyayan did a lot of research, travelling across various lands and much interactions with a great cross section of people to present this work.
It is difficult to say whether the famous sculptures on the temples of India, in love making poses, were inspired by Kama Sutra / Shastra or vice versa.

Thus there is no correlation between the various exotic erotic engagement/ massages, which are essentially a take off from Kama Sutra/ Shastra and Tantra.

While the right path of Tantra can be fairly easily accessible to the seekers from long time practitioners or priests , the left path remains well hidden and rightfully so, as it would be surely dangerous to reveal it to those lacking the training and practice of arduous discipline, needed to be prepared for it and that too under the direct guidance of the master in the left path.