As several obituaries to Charlie Watts have noted, his drumming was key to the sound of the Rolling Stones — he played "with a minimum of motion, often slightly behind the beat," which "gave the group's sound a barely perceptible but inimitable rhythmic drag," that YouTube video above offers a good lesson!
Watts's technique involved idiosyncratic use of the hi-hat, the sandwiched cymbals that rock drummers usually whomp with metronomic regularity. Watts tended to pull his right hand away on the upbeat, giving his left a clear path to the snare drum — lending the beat a strong but slightly off-kilter momentum.
Even Watts was not sure where he picked up that quirk. He may have gotten it from his friend Jim Keltner, one of rock's most well-traveled studio drummers. But the move became a Watts signature, and musicians marveled at his hi-hat choreography. "It'll give you a heart arrhythmia if you look at it," Richards wrote.
To Watts, it was just an efficient way to land a hard hit on the snare.
"I was never conscious I did it," he said in a 2018 video interview. "I think the reason I did it is to get the hand out of the way to do a bigger backbeat."