Donald Trump thought Nepal and Bhutan were both part of India, and had to be corrected at a briefing where he said he knew they were in India.

How do we know?

A TIME magazine correspondent wrote about the episode in extraordinary detail in a piece published on Tuesday. Here's the passage of interest:

"...In another briefing on South Asia, Trump’s advisors brought a map of the region from Afghanistan to Bangladesh, according to intelligence officers with knowledge of the meeting and congressional officials who were briefed on it. Trump, they said, pointed at the map and said he knew that Nepal was part of India, only to be told that it is an independent nation. When said he was familiar with Bhutan and knew it, too, was part of India, his briefers told him that Bhutan was an independent kingdom."

Think that's all? Nope.

It turns out, as Politico has reported, that this briefing took place before Trump's meeting in 2017 with Prime Minister Narendra Modi -- and the US president "mispronounced Nepal as 'nipple' and laughingly referred to Bhutan as 'button'," while he looked at a map of South Asia.

"Wait, seriously, that's what he said?" said Brooke Baldwin, a CNN anchor, when TIME's John Walcott -- the author of Tuesday's piece -- told her about the "Nipple" and "Button" episode.

Take a look.

John Walcott @TIME shares his extraordinary reporting out today 'Willful Ignorance.' Inside President Trump's Troubled Intelligence Briefings. Added bonus: how Trump first pronounced Nepal (nipple) and Bhutan (button). Watch: #CNN pic.twitter.com/nVdzTwlQin February 4, 2019

And Twitter's stand-up comedians reported to duty on time.