Make sure your partner doesn't use the same butt finger in your vagina afterward. Create a chill anal play area. But because relaxation is so key here, trying anal play in a place where you're more likely to feel calm and loose is helpful. Necessity is the mother of invention. If this is gonna stress you out to the point that you're unable to relax and enjoy yourself, try prepping your space ahead of time. Move around until you find one that makes you feel most at ease.