Term used to describe someone who appears to drinking their beer at the same speed as everyone else yet takes very small sips from their pint, normally taking ages to finish it. This is normally used to conceal the fact that they can drink no more, or that they are just rubbish at drinking.
'John you want another pint while I'm at the bar?'
'No thanks mate I'm fine'
'fack me John you've had that pint for hours. Have you got budgie lips today, or what?'