'Welching' is the clunking of the base of a beer bottle or glass, whilst making various grunting or 'pirate-sounding' noises such as arrrrrr, or oarrrrr... etc etc. This is as opposed to 'clinking' or 'chinking' of the
top of a bottle, and it perceived as far more masculine when in a group of lads who are all very
drunk, and in agreement of a certain point of topic.
It is often accompanied by the raising of
one's right elbow upwards, whilst making other peculiar noises, that would suggest that
one has slightly lost the plot.