i.e. Gallagher gurning "SUN-SHEE-IYNE" just so you know what I mean.
It could be a word being mangled beyond recognition just to fit the song, or a particular vocalist's affectation.
One to get started: Paul Buchanan wailing the word "wide" on Saturday Night by Blue Nile http://www.youtube.com/watch?v=1hUKwBeJe78#t=01m16s
I'm sure there's loads