Rimming is not safe. What can you do to make it safer?
Take a shower or bath before having sex, cleaning the anus and just inside the ass hole. Some people like to take an enema beforehand, but this is not necessary to get clean.
With rimming you should always use a dental dam. Not only to protect your self against STD’s, like hepatitis, herpes, syphilis and chlamydia, but also to prevent that you’ll contract intestinal parasites and bacteria’s that will cause health problems.
Never go from the anus to the vagina with your tongue or a finger. Bacteria that are transported from the anus to the vagina are likely to cause vaginal infections. Use a new dental dam if you go from one to the other.
You can put some lubricant between anus and dental dam to make it feel better.