Your question is a logical fallacy. Assuming a normally distributed bell curve a bulk of the male population (80%+) falls within 4-8 minutes of intercourse (not including foreplay).
Hence, you are giving an unrealistic value to the average time that the guy lasts.
Any ways to stop it? I-m now 20 and it seems I now ejaculate about 5 minutes faster... I would like to last about 20 minutes if at all possible compared to my current 5-10 :/
Premature ejaculation happens when a man is unable to control the timing of ejaculation, and ejaculates before he and/or his partner feels ready for this to happen.
Because premature ejaculation can have various physiological and psychological causes there is no easy remedy. You have to try to figure out why it might be happening to you.
Check out the links below for clues as to why you might suffer the condition.
http://www.andrologyaustralia.org/pageCo…
http://www.sda.uk.net/downloads/Ejaculat…
http://www.andrologyaustralia.org/librar…
http://www.urologychannel.com/prematuree…
http://health.nytimes.com/health/guides/…