@oristarA,
I'm going to fail you on that one too, as I have no idea. This sounds like it was written by a British person and they have a lot of slang I'm unfamiliar with. Wellies are rubber boots but wanging isn't a word that I know. Sometimes, the Brits use words that sound alike or rhyme in place of the words they actually mean, it's called cockney slang.
They'll say something like 'apples and pears' and it will mean 'go up the stairs' - or something to that affect. I haven't a clue how to decipher it. Here's a site that will give you more examples.
http://www.cockneyrhymingslang.co.uk/
Again, I'm not sure if that is what this guy is getting at or not. Sometimes when people speak, they'll make up a word just for the hell of it, because it sounds right or sounds like the emotion they are trying to pass off. Onomatopoeia. It's not normally done in writing unless it's completely obvious. This isn't.