If your snake takes pinkies or pinky parts, or whole fish then yes, you should wait a day or two after the bulge disappears. Those items take longer to go all the way through your snake and they are more dense in nutrients.

As far as obesity goes, that's usually only a problem if you feed adults too often. Especially if they are lazy snakes. Snakes are a bit like dogs. They dont know when to stop eating. They don't know when enough is enough so don't worry if your snake seems like he wants more. Just feed like we have suggested (making a bulge, then stop) and your snake should be fine.