In this sentence I can't see there is any difference. I suppose 'slid' is more likely.

They can be the same or have a nuance of meaning. “slipped” would be used in the US as the generic term. The nuance is that “slipped” can mean that you secretly put your hands in your pockets. “Slid” would be a more visible action.

Absolutely. Like a "thief". Oh yes. While you may have never done so, many spooks in an espionage novel many have done so while passing or taking a secret note. This explanation was fantastic and, for me, novel. I'll add that, as I am also not a thief, I have never do such a thing either.

There’s no distinct difference in meaning between the two, but personally I would say “I slid my hands into my pockets” suggests a slower movement, while “I slipped my hands into my pockets” suggests a casual movement.

Hello Ootred, SLIDE means to cause something to move in contact with a surface while SLIP means to lose balance especially on a slippery surface. I hope you do understand me.👍😊