Wiktionary
take the piss
vb. 1 (context Australia NZ British coarse slang idiomatic transitive English) To tease, ridicule or mock (someone). 2 (context Australia NZ British coarse slang idiomatic intransitive English) To subject those present to teasing, ridicule or mockery, or to show contempt.
Usage examples of "take the piss".
The pressure release is to take the piss out of everything and everybody.
I'm sorry things aren't going well for you at the moment, I'm sorry if you're not happy, but there's stuff you can do about that, Spencer, practical stuff, and you just choose not to, because it's easier to just fuck about, and fuck things up, and sneer, and take the piss out of people who are actually trying to do something with their lives .