A tantric therapist probably won't be able to help you until you've taken a long enough break from doing it your old way.
Dr. Lawrence Sank described case histories of men with what he called "Traumatic masturbatory syndrome" in a journal article about a decade ago. He described a pattern of forceful daily masturbation which causes "either an erectile or orgasmic disorder in men."
More generally, about 10% of boys first discover that they can have an orgasm by thrusting their penis rhythmically against a counter, bureau, floor, mattress, or fist, or by gripping it very tightly with a fist. This is usually called "prone masturbation" or "pressure-based masturbation" in the literature.
The classic case is a young boy who discovers he can make good things happen quite discreetly by lying face down with his weight on his penis and rocking or bouncing his body on it. That may work for a typical 10 year old, but gradually, as the boy grows older and heavier, he reaches the point where the amount of force compresses the nerves, causing some temporary numbness. As a result, each time he does it it requires slightly more force, which makes the numbness slightly worse, and so on.
On Reddit and elsewhere online, this is usually called "Death Grip," but in fact most of these boys are not actually gripping the penis tightly with a hand, but are instead pressing it against something firm or hard.
(Girls do this too, and apparently it's not uncommon for girls to learn to masturbate while leaning against a hard object or lying face down on on a pillow, bunched blanket, or clenched fist.)
The (hypothesized) nerve compression appears to be temporary in most cases, and it is often claimed that anorgasmia can be reversed by not masturbating, or switching to a gentler style. However, a lot of the hype around "Death Grip" has come from slick social media marketing for the Fleshlight and other male masturbation toys or "pocket pussies," so it's hard to tell which online testimonials are real and which are fake.
Here's a plausible-sounding example, a post describing a very similar situation and how the OP solved it:
A more "tantric" answer is to stop prone masturbation entirely and combine meditation and open-handed massage, using lots of lube. (Vegetable oil will do.) Don't try for an orgasm at the start. Just get comfortable, relax, and explore all the sensations you can get from rubbing, stroking, tapping, twisting, and stretching different parts of your cock in different ways. The goal is to reconnect and become more aware of all the sensations your cock is capable of feeling.
Some of the ideas in this article may help:
But the common factor in all successful attempts to switch from pressure-based masturbation is to completely stop doing it! You have to give your body weeks of rest with no nerve compression. So it's a good idea to take a complete no-fap break before trying tantric or regular masturbation.
Or you could do the no-fap thing for a month or so, and then see if you can find someone who can give you a really good full-body lingam massage. If you do this, try to get as physically relaxed as possible, close your eyes, and focus all your attention on the sensations inside your body. Even if you don't have an orgasm, the extra intensity of having another person doing it is likely to help you get more aroused and become more sensitive, which can help you when you go solo later.
Whatever you decide to do, be patient and stick to your new routine. Most men who try to switch are successful in a couple of months, but some do take longer.
Good luck!