commonly used in sports to insult players from an opposing team. the sport with the highest amount of sledging is cricket, with one player having to stand in the middle of the opposing team for what could be hours on end. because cricket requires supreme concentration; witty, clever and insulting sledges can be useful in putting the batsman off his game.
some sledges, however, can turn nasty when racism is brought into it, usually by the south africans or pakistanis (but never australians ;)
sledging can occur in football except footballers are usually too stupid to come up with clever sledges.
examples of a sledge:
mark waugh (aus) to james ormond (eng): There's no way your good enough to play for england!
james ormond: maybe not, but at least i'm the best player in my family.
rod marsh (aus) to ian botham (eng): So Ian, hows your wife .... and my kids?
and so on. have to be an aussie or a pom to find them funny