Referee The D

[Triangle NC ref]

Folks,
Starting over in officiating (3rd year in rec league by design) after a lengthy hiatus in coaching and serving as a school principal. Got hooked up with this forum about 2 months ago and now check it 3x/week-good stuff.

One of the points that I've read about from all of you is "ref the D", however I'm unable to find references in any of the NFHS books (rulebook, case book, officials manual, or simplified and illustrated). Tried using the search function, but it is disabled.

Any help would be greatly appreciated. References, threads, etc.

Many thanks,
C