That seems to refer to actually swallowing the animal. The photo I saw didn’t seem to show any quills in the snake’s side, which could be explained by carrion (already dead) porcupine.
As far as American porcupines go, I’ve accidentally run over roadkill porcupines and had quills embedded in my tires. Very glad that they didn’t go into the sidewall instead of the tread.
I’ve had damned mesquite thorns puncture the tread of my tire... more than once!