My fave was always put a sub on hands and knees. Inserted an anal hook with a rope attached braided into her hair. That way when she dropped her head it went deep or she had to be uncomfortable looking up to give the ass relief. Predicament bondage fun. But I see you don’t have those items avail. You could bind ass or other body parts with the belts or tape. Use a rubber band to snap on the actual asshole it self where it’s nice and tender. Although it does take some
Positioning that not everyone can manage. Laying on back legs spread and pulled back usually yields best results. Impact to this same region will result in pain as well. Ass pain is a very vague request. So if you’re looking for internal. Then reducing or prohibiting lube works well. Also fast aggressive full in and out motions.
obviously one can do impact of all sorts to the outside of the ass.