It's called the "Kindly Brontosaurus," and it's nothing short of magic.
Just in time for Thanksgiving traveling, Slate has reprinted features editor Jessica Winter's life-changing tip from 2013 on how to get what you want (i.e. the last seat on that packed flight).
Winter believes that, after successfully using it multiple times, the posture has "hypnotic, even occult powers."
One time, right before Christmas, she kindly gave up her seat on an oversold JFK-to-Heathrow flight for cash and frequent flier miles. She had second thoughts, though, and managed to convince a gate agent to put her back on the flight — even after the gate had closed. How? Well, duh: the Kindly Brontosaurus.
Here's what it should look like, according to Winter: