The semen is a mix of many secretions from different gland present in the testes and the passage. It starts from the testes which is a primary site of spermatogenesis that is sperms are formed in the testes.
Ready sperms are emptied into epididymis and you will be surprised to know this epididymis which is located on the top of testes and can be felt with hand is a 20 ft. long tube which stores the sperms. Epididymis leads to vas deferens which further leads to prostrate and moves on to ejaculatory duct into the root of the penis.
Highly organised sensory end organs that transmit sexual sensation to the brain and brain sends back the signals to the sacral plexus in the spine. The rubbing of glans stimulates sensory organs. The sexual feeling passes through the pudendal nerve to the sacral plexus into the spine and culminates in the cerebrum. Impulses also enter the spine from the adjacent areas like scrotum and perinium which increases the sensation. The ejaculation happens when the signal from the brain reaches the testes. It starts with contraction of epididymis, vas deferens and ampulla to cause the expulsion of sperms into the internal urethra. Then prostate gland and seminal vesicles expels their secretions forcing the sperms forward. These fluids mixed together, comes out of penis with a force the process is called ‘emission’.
It can be primary and secondary. Primary is that you have it for lifelong never had a long duration or you acquired it with the passage of time. Causes can be emotional, performance anxiety, new partners, long celibacy periods, alcoholism, drugs, hormonal and Erectile dysfunction etc. In most of the cases it is short nerve latency time which is responsible for the problem. It happens when the impulses from the brain starts earlier than usual, in those cases the person can not hold much longer and not many techniques or exercises help. These cases require medications.
There are a few methods that can help
But these herbs have different mode of action on different parts of body and brain. Sometimes various parts are involved in the problem so a combination of many herbs may work for you. The medicine that works for one may not work for you because you have different reason for that. So always consult the expert before starting the medication.