Sodomy is when two people do something that's usually considered private using their bottom parts instead of their front parts. It is often when the penis goes into someone's butthole or mouth instead of the vagina. This type of activity is usually done by adults who love each other and sometimes so people of the same gender can also do it.
Some people don't like sodomy because it is not considered natural or right by some people. It is important to remember that everyone has the right to love whoever they want and do what they enjoy as long as they are adults and are not hurting anyone else. However, it is important to know that sometimes people can get sick from doing this kind of activity without being careful, so it is always good to use protection like condoms if you choose to do this.