Oh - let me describe a choak...
My horse will swallow as much food as he can stuff into his mouth and try to swallow it - when I'm NOT looking. While walking him back out to his paddock, he will lower his head and cough. Then look like nothign is wrong. A few steps later, he will lower his head and cough again.
At this point, because I KNOW this horse, I know we are in trouble. And we start energetically walking. Many times I can run my hands up his estophagus (spelled wrong) and feel the bluge, sometimes I can massage it to break up so he can swallow it. Mostly we walk and walk and do not let him go down. I keep periodically messaging his neck, he keeps occasionally coughing.
After about 30 minutes, he will either cough it loose, or I will massage it loose and he takes this deep breath, shivers all the way from head to toe, and immediately wants to go back to eating.
Instead, what he does get to eat at that point is a couple handfuls of rice bran in about two cups of canola oil - which he thinks is crack. We walk for another half hour or so, call him a dork fish, and go home.
We do this about three or four times a year.... the last time he choked it was on CARROTS!!!