I asked TM the same question. He told me just "tilt". What helped me was him mentioning trying to place my scap in my back pocket at launch.
It took me a while to understand. The slip is *backwards* over the ball of the femur. So putting your scap in back pocket or driving your leg forward (and in the process sucking your barrel *behind, under and through*) will get you a hip slip. That's what makes it part of the tilt. Coil over the rear leg. Picture the hip sitting atop the leg. When the leg drives forward the hip (for lack of a more precise phrase) will slip back over the leg, the degree to which it does will be the degree of tilt (and direction).
Considering or trying to teach hip slip AND tilt I think can be confusing, but that's my opinion which I know TM doesn't agree with. But when he does a lot of his videos, like his corner videos, notice how he talks a lot about coil, pullback and tilt and doesn't mention hip slip. My take: you don't actively try to hip slip--it happens if you coil and tilt properly. That's IMO anyway. Happy to stand corrected, still learning