I used to think I was a precummer, and for a few times after I lost my virginity, I definitely was. I'd see the open, waiting pussy, and I would go off, touch free. There were times when I would start spraying the moment my dick just touched vag. Things came back to normal, but I rarely last more than a minute during a fuck. Then I started watching some decent amateur porn, at least with guys. Not at all unusual from the time the guy starts working up his boner to his first squirts for a guy to last only a minute, less, perhaps a bit more. It's almost an exception for some guys last for upwards of 2 minutes. Seems to me that once the jerkoff begins, it's over in about a minute. Same with butt fucking. Very unusual for the top to last much more than a minute from the time he fully penetrates his bottom's ass hole, does his thrusting and humping, that his ejaculation grunts and cum spasms begin. Check it out, see for yourselves. Now this is not to say that guys can't last forever or go on for ages. Hell, when I'm edging with other guys under sordid circumstances, I usually last 1-2 hours before I HAVE to release my wigglers. But I think by and large, once you are committed to the act, ejaculation comes on very quickly as a rule, not the exception.