Hi! Found this through poking around on delicious.

I remember years ago when I began writing fic being schooled by a British fan over misusing the phrase "take the piss." I am American (southern/midwestern/Oklahoman) and we the phrase "take the piss out you," which means to tease or jokingly mislead (similar to "taking the piss," I gather.) I had Spike say, "We're just taking the piss with you," which made my British beta howl. ;)

I made a post on vulgarities (from an American standpoint) a few years ago, if you'd like to check it out: Fun with Cursing.