What will happen to me sometimes, when I have edged for quite a while, if I keep getting really close and having associated emissions of precum that seem to go along with one urethral contraction of the sort that happen during orgasm, is I will shoot some (not most) of my actual cum without having more than one contraction. This happens right after I've stopped jerking, trying to last longer, but gotten a little too close. Usually, because I've edged so long to make this happen, after it does happen, I do shoot a decent amount of cum with my orgasm but not as much as I would have had it not been for the prior release. I have talked to other guys who said that they had experienced the same thing or knew what I was talking about.