Actually Nick, it's just an expression we use to describe the look on someone's face, that's how the engineer looked when he tried to integrate the antique bomb shelter that is my 1975 Peavey into his digital desk. Another example could be…I don't know, maybe trying to describe a young lady who's not so easy on the eye as, ‘she looks like her face caught fire and somebody put it out with a shovel’
…that kind of thing, or, ‘she looks like a bulldog licking piss off a nettle’