It is good husbandry to avoid offering food when a ball python is in blue and to just not offer until the next feeding schedule after they actually shed.

You would also do best to start weighing your ball python to find out more accurately how much they weight and what size prey might do best. How old is your BP and how often do you feed and what size/type of prey?

Never actually rub, lay, place, or otherwise touch prey onto a ball python. This is close to simulating a prey attacking a ball python and it's not exactly the best thing to reduce stress while feeding.