Feeding outside the enclosure is a total myth, passed along mostly by pet stores to get a newb to buy a second tank and more unnecessary accessories! I have 12 ball pythons and have always fed in their enclosures. I've had rainbow boas, kings and corns fed in their enclosures as well. None have ever shown aggression afterwards as I give them until the next day undisturbed. I have also never had an impaction issue from feeding in their enclosure. What do you think happens in the wild...they kill their prey and then find a nice clean spot free of dirt or leaves to eat? Hardly. I've watched mine eat countless times and if substrate is stuck on the prey it almost always falls off as the snake works its way down the prey's body. And when it doesn't it's no big deal.