Hi there, first time poster (not a native english speaker, please bear with me).
I've got a different take on the "minigasms". First off, the term "minigasm" is a good choice (never heard it before) and your definition "orgasm-like sensations and contractions but on a much smaller scale than a full-blown orgasm AND without any (or very little) ejaculation" seems fitting.
My experience with "minigasms" is a bit different from your descriptions though - and they have been bugging me for a long time now, to the point were i was starting some "research" on it, which led me to this forum.
I'm having these kind of minigasms all the time, so often, in fact, that sometimes they get really annoying and distracting and i just want my dick to be quiet and peaceful.
The thing is, generally, i just need to gently touch my dick and focus for a second on it (without being horny at all) and i get a (sometimes quite strong) contraction exactly the way the ejaculational contractions are - but without an orgasm prior to it and with out any ejaculation (or sometimes just a bit of precum). For this the dick doesn't need to be stiff at all. (In fact as a youth i was having lot's of real orgasms with a non stiff dick - i was preventing it from getting stiff by lying on the floor - this doesn't work so well anymore since it hurts).
The only time these minigasms don't work are in the ~15-20 minutes after an actual orgasm. But of course i'm not having them *all* the time, since i still need to focus on them to happen. What bugs me though is that sometimes i get a sort of 'tingling feeling' in my dick and i just *need* to try for those minigasm. This tingling sensation is particularly strong ~12-16 hours after an orgasm. The urge to touch my dick can be really strong then and i need to do so even if i am in public.
The really frustrating thing is that after a while of constant minigasms (like 20-30 in a matter of a few minutes) they start to wear off and they get more seldom - but the 'tingling' remains (and even increases) and sometimes gets really distracting. Often enough i then just need to jerk off just for it to be quiet again (which doesn't always work after i've 'spent' all the minigasms, to make matters worse).
So, i've got quite some mixed feelings towards minigasms as i experience them. Usually they give a nice feeling and the sensation of the minigasm can be quite strong, if only very short lived - and often enough minigasms can drive me horny (and i continue to have them and 'play' with them when i'm nearing an actual orgasm) but i wish i could control them better and not get distracted quite so much (which only ever happens when i need to focus on important matters like writing...).
Until now i thought this would be something everybody experiences, but apparantly this is not the case. Or are people just not talking about it?