Here's a basic neck training routine you can do without neck training equipment. You can do this neck workout as a warm up, a separate workout, after practice for strength and conditioning or even as a cool down before you leave the gym or practice room (of course your intensity would vary depending on what you're trying to accomplish).
If you're a wrestler, submission grappler, Judo player, Brazilian Jiu-Jitsu fighter, boxer or mixed martial artist, you have to protect your neck.
Here's one basic neck workout you can use to help you develop a strong neck. This routine is also great for a neck warmup before wrestling practice and neck bridging.
Basically, this neck exercise routine is like doing 4-way neck exercises using your hands/arms as resistance.
Grapplers, wrestlers, BJJers, Judo players and MMA fighers should spend AT LEAST 10 minutes every day working directly on neck health and/or neck strength.
As a wrestling coach, I make sure all the athletes I coach know the important of neck training and having a strong neck.
Neck training can literally SAVE YOUR LIFE, especially if you compete in dangerous combat sports in which your neck takes a beating (no matter how good or how tough you are).