You're lasting longer than you think, guys.
A recent Journal of Sexual Medicine study that found the median length of intercourse was 5.4 minutes, and according to more research from Rachel Hills, author of The Sex Myth, medians wound up around 7.5 minutes. (Unfortunately, both studies only looked at heterosexual couples, and so they're far from complete.)
It should be noted that the stats don't include foreplay, which as many (all?) people will tell you, is as crucial, if not more crucial, to sexual enjoyment. A 2004 study published in the Journal of Sex Research found that study participants enjoyed 11-13 minutes of foreplay followed by 7-8 minutes of intercourse. That's pretty good, but not as good as what the participants wanted. (Double the time for the intercourse section.)
"I always encourage couples to engage in as much outercourse as possible before intercourse," he told SELF magazine. "The more outercourse you engage in, hopefully the higher your level of arousal and the closer you get to orgasm" before you move on to the main event, whatever your main event may be.
In the end, the best way to have sex that lasts longer is to get out of your head and just get into the moment with your partner.