How long did it last, what did you do, who was with, where did you do it? Do women REALLY want it to last long? I highly recommend a new but ancient technique the Delayer http://www.zexiest.com (For guys only, or women who want their men to last longer)
AHAHA. I could feasibly make love for over an hour. If I did it real slow and kept thinking of non-sexual thoughts. Yeah....... Great orgasm/sex has little to do with the time, so ok, I'd say at least 5 minutes, after that it doesn't matter, really. Foreplay is foreplay, not sex. Longest I ever had was when I was tired and drunk, but not too drunk, and yes, slow fucking, and I didn't even finish, nope, or maybe it just felt long because it was so boring. Don't think about time.
Ideal is about 30 minutes. I don't mean that's it, but something like: 30 min - SEX 5 min - break 30 min - SEXY SEX 5 min - break etc is what works the best for me. Actual intercourse, I don't think I want to last super long... I mean, I'm the one who has to live with that vay jay jay you're pounding tomorrow, but I can spend an entire evening / day being intimate and having sex with breaks interspaced.
if i have the time and the inclination.. jerkin it for like 2-3 hours straight before cumming produces some of the most intense orgasms..