The capacity of the spongy tissue may be diminished due to several factors like:
1. Age: Beyond 55 years, it reduces naturally for a person without any diseases.
2. Frequent/Rare sexual acts or masturbation.
3. Organic diseases like diabetes mellitus, hypertension, cardiac diseases, chronic illness, surgeries and also due to side-effects of medicines taken for other diseases.
4. Psychiatric illness and anti-psychotic medicinal side-effects.
5. Alcohol, smoking, pan and other additives.
6. Nervous system diseases and accidents causing neural damage.
7. Long standing premature ejaculation (0 to 10 strokes after penetration).
8. Using xylocaine based sprays which will reduce the pleasure input.
9. Withdrawing the penis (coitus interruptus) during ejaculation to prevent pregnancy.
10. Not indulging in sexual activity for few days (10 to 30) during childbirth, surgeries etc.