If i do that will the amount of time for i last will decrease drastically?
How long does it take you to finish when you masturbate?
Perhaps you are really used to a very tight grip, and can't ejaculate if you don't experience that tight feeling. You might also be feeling anxious about sex - performing, guilt, something psychological.
If you think it's the grip, loosen it when you masturbate, or stop masturbating for a longer period of time - like weeks, not days.
If it's something psychological, try to work through that, or talk to your doctor or a counselor.