in my opinion power feeding would be when you get it to eat one item and sneak in another item thats either way bigger than normal or the meal is way bigger than it typically should be.
now this doesnt mean giving a snake that could be eating med rats but it will only eat mice so someone sneaks in a small rat behind the mouse.(the meal should be the same size the snake should be eating by size)
now i have had snakes that have actually wanted to eat me every day! those i typically feed them more often than some shy feeders even then i wouldnt try stuffing it with multiple rodents or feeding any sooner than every 3-4 days. but i have adult females that will take med rats more than once a week i would not try it! they only get 1 once a week. sometimes when getting ready for breeding i might give them 1 small rat every 5 days but that depends on weight.