Greetings, Straycat!

I think the first thing to understand is that there is no unitary thing called Tantra. Rather, Tantra is a term that covers an enormous range of things, ranging from religious spiritual practices to understandings of physiology and psychology, all the way to microscopic aspects such as working with the breath, the psycho-spiritual energy, sexuality, etc.

Either you already know what aspect or aspects of Tantra you wish to study, or, I would suggest that you start looking around to see what aspects of Tantra interest you.

One aspect of Tantra that seems to be of interest to many people, for example, is breathwork. For a beginning you can find, online, The Hindu-Yogi Science of Breath by Swami Ramacharaka (William Walker Atkinson). It's also called just The Science of Breath.

To help understand the functioning of our bodies, I can recommend Wheels of Life by Anodea Judith and The Chakra and Kundalini Workbook by Jonn Mumford.

To understand Tantric sexuality from a Western viewpoint, I can also recommend Ecstasy Through Tantra by Mumford.

I would also recommend Tantra by Georg Feuerstein as a general introduction and overview of traditional Tantra from one person's point of view.

I imagine that there are going to be lots of other recommendations, and I would encourage you to read, study, practice and/or consider them all. However, also remember that some people and writers have an agenda (specifically, they think they have the Only True Traditional Ancient Accepted Allowed ® version of Tantra). However, no individual and no group represents all of Tantra. Further, Tantra doesn't "say" anything, so if someone writes that "Tantra says..." or "According to Tantra..." they are, in fact, wrong. They can certainly be accurate by saying "according to the Tantric books I've read and traditions I know, XYZ are the beliefs and practices," but few people will say that.

Tantra can include simply some practices you follow, a philosophy to understand, a spiritual system to follow, or something that becomes part of your being. However you wish to incorporate aspects of Tantra into your life, however you wish to learn is just fine. In short, don't let others try to intimidate you with an "I'm more Tantric than you" attitude.

Finally, in the West, many, if not most people equate Tantra with what is actually just a small part of Tantra, certain sexual aspects. Some people use Tantra as a type of pick-up line. Read some of the books I've suggested and/or the ones others will suggest, and before working with someone else, or with a group, educate yourself and make sure it's something you want.

Namaste!

Regulating your Breath, Movement, and Sounds, can all move your sexual or other energies in different ways. Fast breathing while aroused moves you to faster orgasm. And the reverse with slow, deep, gentle breathing.....

I think this depends on your goals.

Personally, I found classes/workshops and demonstrations to be invaluable. Reading has also been quite useful, but only once I had a context for what was going on.

I've often wondered about private instruction. Fantasized about it, even. But I think I'd want it to come by way of a broader relationship than isolated teaching scenarios.