Unless someone happens to know, I assume this will be speculation.
I just saw an episode of Buffy, the Vampire Slayer on DVD. This episode was filmed in 1998, so let’s use the tech level of that time.
In the scene in question, several of the kids are fighting vampires. Xander is pinned to the ground on his back, holding a stake upright. A vampire is on top of him.
Now, in a single shot, his girlfriend Cordelia falls on top of them, pushing the vampire down onto the stake. Vampire turns to dust, and Cordelia falls onto Xander (somehow the stake has vanished or moved), stares at him for a moment, then starts kissing him. You could clearly see her “suspended” by the vampire briefly, then fall the rest of the way.
The question is: how did they film it? I think you see the vampire actually struggling with Xander a moment before Cordelia lands, but it’s a quick take, and it’s just barely possible that the vampire is entirely CG – although that would have stretched the technology of the time. Even if he was, CG vampires are notoriously bad at holding up real people.
Best I can come up with is that the vampire was completely CG, and Cordelia was on wires to suspend her “fall” briefly. But that seems unlikely given the tech level of the time. Anyone have better ideas?