Spiking the ball.

[Theisey]

One step back and thrown directly to the ground in front of himself is immediate.
Anything else is a backward pass or it two or more steps taken, then an illegal forward pass.

Given this is high school level ball, I'd personally let it go if it was close or as they say when if doubt about being forward.

Be nice if NF would consider allowing a spike from a shotgun like formation as does the NCAA. Why make it difficult for the younger players.