Sexual Tantra is not "Tantric sex." Learn that difference and you can legitimately claim the first degree of sexual enlightenment.
I introduce this thread for all those, including staff and visitors alike, who would benefit from an open, polite, and revealing discussion of first-hand experiences of kundalini or what you may have taken for such. I will personally delete any salacious remarks or quarrelsome comments.
To get the topic rockin' 'n rollin', I propose that you take a look at the vid below, going to 27m if you can't stand to watch the entire clip.
https://www.youtube.com/watch?v=KPgEoDt_Duc
As for the serpent power, you get it through your feet in tolerable doses, naturally. You get it in and out of sex basically in two modalities: melt and surge. Melt is best, and ideally shared. Surge can be a challenge. I can assure you that it hurts. Or better said, it smarts. It jolts and starts. It is unbearable and yet somehow you bear it. That ecstasy verges on pain, but it feels so good you want to die in it.
Apart from my own first-hand experiences, which are many and diverse, I can also attest to witnessing the surge blast through others with convulsive force. On one occasion, it happened to someone in the presence of a cording in the Serrania de Ronda, Andalucia. This cording:

A feature of this cording, not shown here, was a loose thread hanging down vertically. It was left that way intentionally. Feeling mischievous, the Nagual told the creature for whom this cording had been constructed to hold the end of the thread if she wanted to feel 40,000 volts. The convulsions that followed lasted about 40 minutes with some spectacular special effects: for instance, I watched her shapeshift back to the age of fifteen or so, complete with a face showing altered features and adolescent complexion problems, and then warp shift again through her twenties and thirties back to her current age. The cording was on a steep hillside and at one point she nearly rolled out of my reach down to the bottom of the ravine, thirty feet below.
On a different occasion, and in a rather more lascivious setting, another specimen of the female gender went into thrashings so strong that I had to lay on top of her to keep her from crashing off the bed and cracking her skull on the floor. So much for surge. I advise you to cultivate melt.
I know that I am probably opening quite a can of kundalini words with this thread. Let's see how you handle it. The fact that the essential intel on this topic is now, and always will be, for staff only may annoy some visitors. The truth is, what I can tell the world about kundalini and sexual Tantra came to me at considerable price. I earned what I know, I came through it with my sanity intact, and what I can say now about it doesn't come free.
shivering regards to all, JLL