Where can I find good 'Zero x Ciel lemon fanfic'?

There are specialized fanfic forums related to the series that Zero and Ciel are from. These forums often have sections dedicated to fanfic sharing. You can also try Tumblr. There are many bloggers on Tumblr who are into the same fandom and might share or recommend good Zero x Ciel fanfics. Just be aware that the quality can vary widely, so you may need to do some sifting through to find the really good ones.

You can start by looking on some well - known fanfic websites such as Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, and there's a good chance you'll find some great Zero x Ciel fanfics there. Another option is Fanfiction.net, which also has a wide range of fan - created content.

AO3 is a great place. The tagging system there allows you to easily search for Zero x Ciel fanfics. You can also filter by different criteria like rating, word count, etc. Additionally, some smaller, more niche fanfic communities dedicated to the fandom might also be a good source. You can find these by searching on social media platforms for groups or pages related to the Zero x Ciel fandom. However, always make sure to follow the rules and guidelines of these platforms when looking for fanfics.