I've always needed to rest a bit between orgasms--a few minutes of recuperation to build up towards orgasm again--but I don't always lose my erection or my sense of arousal. I thought this was normal, especially for teenagers and younger men. I thought that period of rest was what was meant by the "refractory period." I didn't realize that loss of arousal was a necessary component of the refractory period, or that it was considered impossible for men to stay aroused between orgasms or to achieve 2 or more orgasms on a single erection.
I've also seen porn vids where the actors seem to have 2 or 3 orgasms in a scene without resting in-between, although there could be editing involved. (This seems to be a common feature of Kristian Bjorn films, where each actor in a scene seems to have at least 3 or 4 orgasms.)
For some reason I thought that multiple-orgasms meant having several orgasms in rapid succession, one immediately after the other. I guess I've been laboring under a misconception. Perhaps I have been multi-orgasmic this whole time without knowing it? Lucky me.
Having said that, most of the time after orgasm I'm tired and have lost interest in further sexual stimulation. However, it is not uncommon for me, after having achieved orgasm, to feel like "that was really good, I want another one." (For me, it's not unlike having a really great cup of coffee or tea, which for some reason is more satisfying than usual, and deciding to have a second cup.) The key for me seems to be how horny I was before I even began. If I'm in one of my high-libido phases (which are all too infrequent these days), and I'm feeling highly-responsive both physically and psychologically to sexual stimulation, then I'm much more likely to stay aroused after orgasm and to go for another one.
However, I'm not sure if I've ever gone for a third orgasm. Even if I could manage three, I doubt I could do more; I would have to force myself to do it, and I'm not sure why I would want to do that. Just because I can? I'm not sure that's a good enough reason.
Also, I don't think I could manage to do what multipleman does and have several orgasms within a short period of time like 10 minutes. Again, I'm not sure I would want to.
Sometimes, after orgasm, I'll stay erect for quite a while, even if I've decide I don't want to go for another round. During those moments the erection is a nuisance, like when I'm trying to fix a snack and the damn thing keeps hitting the counter. This is not typical, but not all that unusual, either. Sometimes I'll jack off again to make him go away, other times I'll let him fade on his own.