I need British slang help?

And your question is?

Assuming you're a colonial, John is a guy's name. Slang is loo, bog, #1 is "point Percy at the porcelain" (doesn't work for lasses), "shake hands with myself", piss, wet the wall, #2 have a crap, have a sit down, meet the queen, big job, "just going to do the Time's crossword", kack, **** and no doubt many others, which I'm sure you'll pick up (not literally I I hope) while you're over here. Enjoy the foreign language called english. Most of these words are also quite useful in describing something or someone, usually in a less than friendly way. I'll let you work out when you get here which you use in polite society and tea rooms. I personally wouldn't know, they don't let my type into either.