Twisted gut

twisted gut... its where they gobble dry food and it expands in their stomach where it can be nasty and painful

How common is this

I'm not sure, can be fatal though   

It's more common then people think, there is bloat and the stomach twisting you can get both together and one without the other.

It's where alot of air is taken in when eating or drinking, also this is why you should never walk or exercise a dog just before or after eating especially in a deep cheated breed who are more prone to bloat

It is fatal if not treated in time

I take it you mean Bloat which is a gastric torsion, yes this can be fatal if not dealt with very quickly.

What do i do if i suspect my dog has bloat?
Bloat is very serious and can kill a dog very quickly so immediate action is essential if you suspect bloat.

If your dogs stomach is swelling out, s/he is retching, bringing up white foam and bile, seems in great distress, is unable to pass stool and is panting heavily for no reason it is possible s/he has bloat (or a twisting of the stomach.) In cases of bloat it is essential to get your dog to a vet immediately as this is classified as an emergency. While waiting for a vet or on the way to a vets try to keep your dog standing and moving.