Finally, use your common sense. The rectal wall curves and is thin, be aware that long, hard objects can tear your insides. Don't wear any jewelry on your hands, and cut your fingernails if you are going to put your finger in someone's anus. Experiment, there are many more positions and techniques to try. Find the one that suits you best.
Good communication is the key to such discovery, and a manual or video can help as well.
For many people, anal sex is the ultimate taboo. Buttfucking makes it sound crude and dirty, sodomy sounds technical. In the 1990's, anal sex has been given the bad rap because HIV, the virus that causes aids, is most easily transmitted by anal intercourse. But some people love anal sex. Others hate it.