Hello, I can understand your concern. Your problem is suggestive of a condition called premature ejaculation. A condition in which the time for ejaculation is short and spontaneous discharge on minor arousal is common presentation. Stress and anxiety are two major risk factors for premature ejaculation. However, in many cases there may not be any specific cause seen.
Next Steps
You must consult with a sexologist in detail. For detailed instructions on management you may consult with me directly here on practo.
Health Tips
With suitable medications and instructions it can be completely cured.