Snakes stay in "feeding mode" for a few minutes after they are done feeding. You can either let her relax for a few minutes, or just pick her up and ignore the behavior. It becomes a "problem" when the snake is still hungry, and goes after any moving object- like your hand!
I have always fed in separate containers from the first meal forward and not had problems. My snakes just get used to it. I like to feed outside the viv for several reasons. You handle the snake and detect any problems by visual inspection. You can get a weight at a scheduled time, and get in the habit of weighing regularly. The snake gets handled, and gets used to being handled. Babies (and adults) can be trained to come to the front of their viv on feeding day when you knock. it's kind of fun. While the snake is out, you can spot clean, take the water bowl out and wash and refill, or even do a full bedding change.