You keep losing your grip.
2 seconds sound clip from the The Sword in the Stone (1963) movie soundboard.
You can hear this line at 00:26:09.760 in the Blu-ray version of the movie.
Quote context
[...]
- Don't you even remember the boy?
- Can't you remember one blasted thing?
- Oh, now, just a moment. I...
- Oh.
- Loose in the saddle, knees in tight, weight forward and stay on target.
- It's not a mere matter of muscle, son. Jousting is a fine skill. It's a highly developed science.
- Science, indeed. One dummy trying to knock off another dummy with a bit of a stick.
- And the Wart's just as hot for it as the rest of them.
[...]