I would love to have anal sex with my boyfriend but I want to make sure it's clean sex can I douching or enema and cleaning anus and a bit of rectum?

Water enema is safe. Feel free to use a water enema to clean yourself before being intimate. Some people evacuate completely after each bowel movement and do not have any issue with "cleanliness" during anal sex. Other people may need the help of an enema beforehand. As you get to know your body better, you will be able to determine if enemas are optional for you.
Anal sex. Before engaging in anal sex, check out http://www.womenshealthmag.com/sex-and-relationships/what-anal-sex-is-actually-like-from-women-whove-tried-it, http://www.cosmopolitan.com/sex-love/news/a17749/anal-sex-misconceptions/ & http://www.askmen.com/dating/vanessa/28_love_secrets.html. Then http://www.webmd.com/sex/anal-sex-health-concerns. Make him wear a condom & change if switching to vaginal sex.