"When in doubt throttle out" is a saying that's been around since I was a kid riding on the tank with my uncle on his old Honda three wheeler ATC with no helmet and feet dangling next to the hot exhaust pipe. Man, those were the days.
But what does it mean exactly? Well, it is not to say that if you don't know how to ride it is as simple as hitting the gas and taking off, I'm sorry to say. But it does help in a lot of situations while riding dirt bikes especially with soft or loose terrain like sand or gravel where your front end starts digging in and it feels like you are losing control of your dirtbike.
What does it do to help? After riding for many years and being "in doubt" in a few situations I figured out that it help keep your front end light and free from digging into the loose ground that gives you that out of control feeling and also helps keep you upright on your bike since losing speed can lead to tip overs.
There are a few drawbacks to this technique, and one of them is you do have to get comfortable with a little bit of that out of control feeling. Your bike will get squirrely under you while it plows through all that sand and gravel and your hanging on for dear life and keeping all your weight on your back tire, again to keep you front end light. Remember it's all about that front end.
For us who ride quads, does it help? Well, the short answer is YES while we don't have as many issues in the loose terrain "When in doubt throttle out" can get you out of some tight spots where your back end doesn't seem to want to cooperate and wants to bounce around a lot. Hit the gas and keep your weight back this will help keep traction and get you over that tricky whoop section, past those round river rocks and get your front end across that big rut that came out of nowhere.
So, in the end, I can say that "When in doubt throttle out" is some great advice for any rider. Just don't think it's a fix everything solution. Be smart about it and ride safe.