Is “point percy at the porcelain” a common idiom in the states?

American here: I've never heard it.

No. I have never heard this in my life.

Not at all, but I can guess what it means.

No. Not at all. I've never heard anyone say this in my life.

Never heard it. Seems like it might be endemic to Australia?  >This is one of the numerous slang phrases related to sex or drinking coined by the Australian comedian Barry Humphries during the 1970s and onwards. Humphries' Barry McKenzie column in Private Eye contained a fictional account of the doings of 'Bazza' McKenzie - the role model for the later creation Crocodile Dundee. In 1972, the character was used as the lead in the film The Adventures of Barry McKenzie, which contained a list of similar phrases:

It's much more recognised in the UK. Common in the 1970s-80s, but it's pretty out of date now.

I’ve literally never heard it, or read it, in my 58 years.

How do you even use this idiom? Like, when you're having a good time w/ your friends and this comes up, in what context? How would an exchange go between two people and one of them says it?

I'm fairly sure the only time I've ever heard this is on older UK comedy shows. I've never heard an actual person use this phrase in real life. Been watching Miranda have we?

This is something my buddies and I would jokingly say in middle school (6th grade, so maybe 11-12 years old or so). I haven’t heard it in 20 years.

I don't think so.

What??

I only encountered it in a list of euphemisms for "urinate", and I thought it was funny. Outside of my family laughing about that list, I've never heard anyone use it.

I've never heard this and don't know what it means

Absolutely not.

Never heard it

Nope. Never heard that in my life.

Nope

No it isn't If you preface it with "I am going to go and ..." as you get up and head for the restroom it'll be very clear what you mean. Probably a bit rude for mixed company. With some cool friends in a casual environment, it'll probably knock em dead.

Where do you find these things?!?

lifelong nyer & never heard it. maybe it’s regional?

Not at all and I’m struggling to think of what it means

I've never heard of this in my life. I imagine it means "pee" but...no. Don't say this.

Is that why Percy Weasley has that name? Because he’s a “knob”?

No

Absolutely (and somewhat obviously) not.

I’ve never heard that in my life where did you hear that?

Just make sure you've finished driving the porcelain bus first!

American that’s lived in the northeast and Deep South, I’ve never heard the idiom/phrase nor ever even seen it written before.