Victorian erotica is like grown-up stories with pictures that were popular in the 1800s. They were sometimes called naughty books or pornographic literature because they had pictures and stories that were about sex. They were kind of like magazines or books that people would buy at the store, but they were only for grown-ups because they had words and pictures that were not appropriate for kids.
The people who made these books and pictures were called artists and writers. They used special printing machines to make the pictures, and printed the words on special paper. The pictures were often of people who didn't have any clothes on, and the stories were about things that grown-ups liked to do when they were alone.
Some people might not think it's okay to read or see these things because they can be inappropriate or make some people feel uncomfortable. But some other people like to collect them and study them because they are interested in the history of what people liked a long time ago. The important thing to remember is that if you ever see or read anything that makes you feel uncomfortable, it's okay to tell an adult you trust.