Google anal peripheral prostate massage, learn the details, if you think it will help you in any way you may do it 3 times in a week.This will take care of anal sphincter and anal passage.This can be done with you middle finger.usually area of 2 inches is erotic in anus.
Not dangerous unless it can get lost and not come out, or scratch you. The anal region is not very clean, you don't want to do anything that will cause bleeding. Couldn't you find any sex toys that are somewhat more rounded?