When you are engaged in sexual activity, it's important that you relax and surrender completely to the feelings coming up. During this process there will be an increase of slow brain waves such as delta and theta waves seen on the middle brainmap above. The stronger the waves, the more orgasmic energy you can hold in consciousness before it travels downward and spills over in the body in the form of an ejaculation.
When you relax and open up during sexual stimulation, changes first take place in the etheric body. The Kundalini energy which is coiled up like a snake at the base of the spine in the root chakra starts to rise to higher levels passing through the chakras. Since Kundalini is the energy circuit in the etheric body (much as the blood vessels are the energy circuit in the physical body) the changes in energy initially take place in the etheric or emotional body.
If the person relaxes and surrender to the pleasurable feelings, there will be physiological changes such as an increase of the parasympathetic activity in the Autonomic Nervous System. If you are not relaxed in the situation, the energy is blocked, possibly leading to frigidity and impotence. In case of relaxation and surrender, the brain changes its activity toward more alpha and theta waves. These changes indicate better access to the body and the feelings. Now, as the energy rises and increases its momentum, it’s important – through meditation - to hold the energy in that space of consciousness without releasing it.
When you get very close to orgasm, and the male gets close to ejaculation, the feelings will be overwhelming and the brain tends to shut down and reverse the energy which will then take a downward course and seek release through the genitals. These energy changes are mediated by a small structure deep in the brain called the hypothalamus which controls the balance of the Autonomic System (ANS).
According to a principle called reciprocal innervation, an extremely high activation of the frontal hypothalamus and thus of the parasympathetic system, will create an overflow of energy activating the posterior hypothalamus which stimulates the sympathetic nervous system. This will make the energy rise to higher centers and this process is accompanied by very fast activity in the EEG (beta and gamma wave frequencies up to at least 42Hz).
So, initially you will see very low frequencies when the energy is activated in the lower chakras. When the energy rises to the higher chakras, very fast frequencies will take over (see above brainmap). The sexual feelings and the energy is now so overwhelming that most people cannot contain it anymore. Once more reciprocal innervation in the hypothalamus shifts the balance toward more parasympathetic activity. The brain's activity is shut down, and the energy takes a downward course. These changes are automatic and fast and will quickly lead to a depletion of the energy and in the male to ejaculation.