Hi Socs
It’s very difficult to make an any informed explanation of behaviour from a verbal description. Even video clips are often to short to tell what’s really happened.
At a guess, I wonder whether the the smaller one was a male and the larger a female. The smaller (possibly last year’s younster) didn’t immediately realise that it was a female and so butted it, or maybe just hadn’t outgrown it’s hoglet behaviour and thought the large one might be willing to share (adults often will share with hoglets, or even give up the bowl to them, but once they get a bit bigger all that stops). The small one then realised the larger was a female and was overcome with hog emotion (maybe, think teenager) – hence the strange pose (which I have to say is quite difficult to imagine without seeing it, but it sounds similar to behaviour I’ve seen). Sniffing round the larger hog in a friendly way, sounds like the beginning of hedgehog courtship behaviour (hence my thinking large hog was female, small hog male).
Large, mature, female hogs will not always react to very small, young, males as they would with more mature male hogs – i.e. start jiggling their legs up and down and reversing. They may, understandably, want the best father for their hoglets and not think a youngster fits the bill.
All, of course surmise, with so little to go on, but mostly possible.