Depends on the guy and the position! The position and angle that gets me off the best (girl on top) doesn't work as well for the guys I've been with, which is great because they can go for as long as I need provided that I keep them hard, and then we can roll over and they can get off in a better position for them. Love it.
I was once with a guy who never lasted more than 5 minutes, and usually quite a bit less than that. If I gave him a blowjob and then we waited a half hour, he would last more than a minute, so I ended up giving him a whole lot of blowjobs. They became such chores! I'm glad to not have to deal with that guy anymore. If I found myself with another partner with the same problem, I am sure I could eroticize the situation and make it hotter for me, but as a teen it was annoying.