"Imaginary" 3 foot restraining line? NFHS Throw Ins

[CO REF]

Please forgive me if this is an easy one and I am just not looking in the right place in the rule book.

If the player throwing the ball in bounds, has limited room to move backwards, do we have the authority to implement an imaginary restraining line?

And if so then now this imaginary line falls under all of the normal restrictions/penalties/enforcements for reaching through the plane, etc.

If so could someone direct me to this in the rule book?

Thanks.



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