Funnily enough, we have learned a huge amount about first century Rome from the graffiti in Pompeii and Herculaneum.

Here's the family-friendly stuff:

http://ancientgraffiti.org/Graffiti/

Here's the absolutely filthy stuff:

https://kashgar.com.au/blogs/history/the-bawdy-graffiti-of-pompeii-and-herculaneu