I do NOT allow my students to strike the larynx in any form or manner. PERIOD.
The demonstration of the Nozo no Ushiro Nage in the Budoshin Jujitsu Black Belt Home Study Course video set was choreographed to demonstrate how the technique would work in a life/death situation. The video also shows simulated strikes along side the neck so the student can practice the technique without actually striking his opponent. Make sure you step forward with the same foot on the same side of your body as your extended arm, thus maximizing your ki flow/momentum/balance and destroying the balance of the opponent without exerting any more effort.
When students are initially taught this technique they are taught to PLACE their middle finger on the jugular notch. The other fingers support the middle finger. If the defender wants the person to go backwards, the tip [not print side] of the finger gently pushes back towards the back of the opponent’s head.
If you want the person to go straight down, reach behind the jugular notch and push down gently until the person goes down.
On the street this “push” can be done quite quickly and effectively, but it should never be used as a strike unless you “fear for your life”. A simple push can be very effective and produces a good “gag” reflex at the same time.