Definitely not. The manga portrays Ciel and Sebastian's interaction as professional and duty-bound rather than romantic, so there are no kisses between them.
I recommend "The Creation of the Devil's Tail" to you. The main character, Charles, not only created Sebastian in "Black Deacon", but also created many characters related to "demons". This doujinshi novel is very interesting! I hope you like this fairy's recommendation. Muah ~😗
There's 'A Dark Affinity'. This fanfiction takes a unique approach. It shows female Ciel's vulnerability and Sebastian's complex feelings towards her. The plot twists keep you on your toes, and the descriptions of their encounters are quite vivid.
In many Sebastian and Ciel fanfics, couple fights can be intense. They might fight over things like loyalty, as Sebastian is a demon bound to Ciel. For example, Ciel might suspect Sebastian of having ulterior motives. Kisses, on the other hand, are often used to show a deep connection or a moment of vulnerability. Sometimes it's a way for the author to show the complex relationship between them. A kiss could be a sign of Ciel's trust in Sebastian in a very different way than their normal master - servant dynamic.
Power dynamics is also a big theme. Sebastian is a powerful demon and Ciel is a young earl. The way they interact with each other in terms of who has the upper hand, and how that changes over time is often explored. For instance, in some fanfics, Ciel tries to gain more power over Sebastian, or Sebastian uses his power to protect Ciel in unexpected ways.
One interesting plot idea could be a time - travel scenario. Sebastian and Ciel are sent back in time to a period in the Phantomhive family's history that is shrouded in mystery. They have to navigate the past, deal with their ancestors, and also face the fact that their actions in the past could change the present they came from. Another idea is a role - reversal. Ciel becomes the demon and Sebastian the human servant, which would completely turn their relationship dynamics on its head and lead to all sorts of comical and also thought - provoking situations. A third plot could be a crossover with another popular anime world, like they end up in the world of Naruto and have to adapt to the ninja way while still maintaining their own goals and relationship.