US President Donald Trump is notorious for his unusual handshakes.
He's become known for his twitchy style, which often looks like the Commander-in-Chief is trying to tug the recipient's arm off.
During Japanese Prime Minister Shinzo Abe's White House visit, Mr Trump's handshake made headlines for its awkward length and the look on Mr Abe's face upon eventual release.
Earlier in January, a video of Mr Trump congratulating Supreme Court nominee Neil Gorsuch showed him wrench the judge's body towards him in a vigorous greeting.
Now, a black belt from the Relson Gracie Academia de Jiu-Jitsu has posted an online tutorial video showing how to defend against the "arm drag handshake".
"I wanted to share a technique today - as I'm scrolling through my Facebook feed I see this video and it hits me. I've got to teach the defence against the Donald Trump handshake," he says in the YouTube video.
"Somebody grabs your hand and they pull you in - you've seen the awkwardness."
With the help of a purple belt, he demonstrates the "goose neck" wristlock he says will defend against the handshake.
"Now I'm not suggesting you do this to the President," he says.
"As he grabs really hard and pulls you in, I go with it. I step in with the outside foot, I wrap around the elbow. As I do that, I'm going to block his arm from here, I bend the wrist in, the other hand wraps over the top of the knuckles and boom - now you have what we call a goose neck.
"Secret Service, I promise: if I meet the President, I probably won't wristlock him."