No prep is needed for anal stretching other than having a normal bowel movement. Setting the stage for success includes a positive mood and mindset, as well as your surroundings. Dr. Goldstein usually recommend doing your exercises in the shower, while warm or hot water is running or right before a shower, both of which can help aid in relaxation. Be sure to have all of your supplies ready before you get started and remember that this includes lots of lube (this is paramount).