Updated: May 28, 2020
Kundalini is actually Earth’s vital force that raises through the spine and goes obviously through all chakras from C1 (root chakra) to C7 (crown chakra). Since we are in the 3D vibration world, the chakras are open just in the range 5-20%, where C1 is open on average just 5% meaning the link with Mother Earth who maintains life in our bodies is weak.
The large majority of “spirituals” whether Eastern or Western, work in meditation only on the upper chakras C4-C7 and disregard or at least invest little time if any in the lower chakras; many times they even don’t know even this detail. True that these lower chakras are much more difficult to open than the upper ones, and they don’t bring results by far as fast as working on the upper ones. Therefore there are lots of confusion concerning lower chakras, including the sex subject.
The C2 chakra (svadhistana) is dedicated to emotions and, using Earth’s life-force that comes from C1 it feeds all the organs around it, including the reproduction organs that includes the sexual obviously. Since the average 3D person on Earth is physically centered, meaning has full attachment to his own body and couldn’t care less about the soul (subject of developing/opening C4-C7 chakras), he is sensitive to energy movements in the C1-C3 chakras (physical level including survival-C1, emotions-C2 and will-C3) and much less in the C4-C7.
So the average person feels strongly when there is a surge of Kundalini life-force, or additional energy coming from food, drinking, drugs or other sources through C2 chakra since it overloads it and gives peak feelings like during orgasm.
An orgasm is actually a very short (seconds) outburst of Kundalini energy that flashes throughout the spine from C1 to C7 and as such unloads the C1 and C2 especially from their surplus of energy.
This mechanism was designed in human bodies like this since one needs HUGE amounts of life-force energy to conceive a new life, it takes about 1/3 of vital life-force of a body when doing this and that’s why average people are exhausted after an orgasm.
Actually for that few seconds of orgasm the individual is truly “enlightened” (no thoughts, peace inside, no worries, bliss feeling, etc), but falls back immediately because his body can’t sustain this kind of energy for long, and his energy conduits are energetically clogged because of low level food and drink he eats/drinks, and 3D subconscious emotions he harbors.
This is why energy movements in C2 are felt strongly by the individual since it governs emotions especially sexual ones since they drain so much energy. Since this world is just 3D as vibration (3.5D actually is the average human soul and body) it is centered around the lower chakras and hence the strongest feelings (energy movements) are in these chakras and especially in C2, sex is paramount for all people and govern their life, where the sex subject occupies many of their thoughts.
Actually, not the sex subject is wrong by itself, ultimately it’s natural since it was programmed in humans from start and serves the species continuity, problem is how humans handle it … Tantra yoga tries to correct this and also other more mature spiritual schools.
In the old days of India people had no scientific background, so explanations as above would have been meaningless for them. Back then everything beyond their immediate experience was considered magic and associated with a god/goddess. Therefore kundalini (Earth energy) was associated with goddess Shakti and people had as such an image/deity to pray to and hence get an idea about what Kundalini was …