Steve Parkes, you guessed it "shag" in the U.S. is not the same as in the U.K. In the context in this thread, it is a dance, 1960's era I believe, that was regionally popular. It is also used to name a type of haircut and a type of carpet, in both cases apparently related to "shaggy", meaning essentially "long, stringy, and unkempt". It does not register in the American psyche as a nasty word, and is probably hardly ever used here as such, although a fair number of us are aware of its meaning overseas (many only because of the Austin Powers film title).