Any time I get a regurgitation it's handling after feeding. But that's holding the snake and letting him crawl around in your hands and squirming around. I've handled right after a meal but only to pick him up gently and put him in another enclosure to clean up the mess, then put him back without holding more than a few seconds. With ball pythons it's easy, but with a large retic or a squirrely King snake it's harder to keep them still while moving them, with those guys I tend to just clean up around the snake.