That precise moment of penetration is very difficult to describe indeed. Since it's a completely unique sensation, it's almost impossible to liken it to anything, even using the most hackneyed of homilies - metaphorical description of penetration has been commonplace since Fanny Hill and well beforehand, although what I (at least) experience is so unique that it not only defies metaphor, but takes it outside, beats it up, steals its cash and shags its mother.
And now who's hackneyed, motherfudgers?
Anyway. What I'm referring to isn't really penetration itself, but the initial few moments of penetration - the ones you almost miss, in a way, when the tip of the head of the penis is just inside. There's something about the movement of the labia majora (and the inside walls, to an extent) which is unlike anything else, and which is, therefore, so hard to describe.
It's only that moment. Anything else I can kind of do. I described my first ever time (using a very thick condom) as like dipping my penis in an upside-down (she was on top) bucket of warm water. I feel comfortable describing how the warm, soft wetness of the inside vaginal walls contract and mould themselves around the shape of my penis inside her. I'm fairly confident with orgasms, having laboured to describe those since my first year of blogging. I'm even pretty good at describing blowjobs, particularly from a giver's point of view, although I mostly have to guess at that.
The moment of insertion's what I'm trying to get at. Last night I experienced it several times. Each time was the same. It occurred to me at one point that I still had no idea how I'd describe the feeling. And then I hit upon it.
I described the feeling as being like a small explosion.
Maybe that's more like what an orgasm feels like; perhaps it's lack of another explanation. But it feels less like going into something to me than it does changing state. The sensitivity of the tip of my penis (once my foreskin's rolled back) amplifies feelings tenfold, and the way the vaginal opening reacts upon penetration - something I once described as a "pleasant spreading sensation" - suggests to me, for a millisecond perhaps, that there is in fact something heading outwards from the tip, and that whatever the speed one cares to enter at, an explosion(ette) is the best metaphor I can think of.
Of course, there are more to come after that. But I'm claiming this one before anyone else gets their hands on it...
...and what better way to describe the beginning of a bang?