1. Do Not use any jelly or numbing cream to alleviate pain.http://www.cheapnumbingcream.com/Speed-Numb-Numbing-Cream
Yes, anal sex can hurt, but that does not mean you should make it numb during the activity. If you do this, you might not notice if you've already had a severe injury. The best alternative option is to use good lubricants.
2. Dont do it if you have hemorrhoids.http://www.health.harvard.edu/diseases-and-conditions/hemorrhoids_and_what_to_do_about_them
If you ever decide to have anal sex, you could experience bleeding due to your hemorrhoids.