Billie won't mock him for holding it like that. It takes time to get used to a weapon, that's all. She'll go and retrieve the knife a second time and, again, return to stand by Strange's side.

"Sounds about right," she agrees without any sort of academic magical background whatsoever. It makes sense, though, doesn't it? Figure out the rules of something without magic, then make the magic streamline them. She holds the knife up a third time but doesn't throw it again. Instead, she holds her arm still, poised as if just about to start the throw. Wrist and forearm align, held stiff, rather than her leaving her wrist loose.

"Now, when you throw something, you don't want to flick it with your wrist. I don't care how it's written in adventure novels, that isn't how it actually works." That said, she draws her arm back, moving to position her throw, then pauses again. She'll do this for every step of what, ultimately, is a motion that takes all of a second, explaining it as she goes. It sounds simple, it looks simple, whether or not it ends up being so is up to Strange and how well his first few throws go.

Which is why, once she's done explaining, she's taking a fairly large step back.

"Alright, you try. Just work on getting it to hit the board."