taking the piss

Taking the piss Chiefly British
Vrb phrs.
1. To ridicule, to tease, to make fun off. Cf. 'extract the urine'.
2. To take advantage of, to exploit. E.g."Just because they like looking after their grand children, doesn't mean you can dump the kids on them every weekend whilst you go out clubbing. That's just taking the piss."

Yeap, that's british slang and here's the explanation about the origin of the expression: http://www.worldwidewords.org/qa/qa-tak2.htm
Synonyms: Take the Michael out of... or Take the mickey out of ...

Take the mickey out of someone
1. to tease. Mickey represents Mickey Bliss, Cockney rhyming slang for piss. The expression then is a euphemism for take the piss.

Yes, the expression was briefly mentioned in our meeting yesterday, among other topics sprinkled with countless cocktails to keep our kidneys happy. It was an explosion of fun and I was in a very good mood. Great laugh and piss taking and I, too, was at the receiving end of irony!
I've also been called a poet in a jester's costume, a description that I acknowledged with a smile and embraced as a compliment. Eh, pleasantries between fellow poets, what do you know? ;-)