I've been practicing tantra informally for a few years. I've been able to move the kundalini (sexual) energy up my body slowly, one chakra at a time. It's difficult when you hit the heart chakra because you want to fall in love, or think you are falling in love... or something
Now I've reached the crown and experience incredible full-body orgasms with what I can only describe as a ball of energy radiating out of my head, an out-of-body experience... words are really silly, they don't do justice, so I won't try. I will say that what's happening in the groin area is becoming increasingly less important.
I imagine it's very difficult to find a true tantric provider because the authentic experience involves boundary dissolution to a degree I imagine most would not be comfortable experiencing, unless they know you
very well.
For those interested, I'd like to make a couple of suggestions: 1. Do
not attempt to prevent ejaculation until you are very experienced and 2. Check your motives. Tantra is a profound spiritual practice and if you're just in it for the physical thrill it will only take you so far.
peace
Phaedris