I'm not sure which Slam Dunk Doujin novel you're referring to because you didn't provide a specific title or plot. But I can give you some tips and suggestions that might be useful to help you find the joke you need. First of all, if you know the plot of the novel, you can try to search for relevant jokes or cold jokes to find humorous elements related to the plot. You can enter the title of the novel or plot in the search engine and use the keyword "Slam Dunk Doujinshi Jokes" to find relevant search results. Secondly, if you're not sure which novel you're looking for, you can try using an online novel reader or app and search for jokes or cold jokes related to the novel you want to read. These readers or applications often have search functions and filter that can help you find text related to the novel you're interested in. Finally, if you still can't find the joke you need, you can try to find relevant jokes or cold jokes on social media and share them with the audience you want to read. These social media platforms usually have many users sharing interesting content and may find jokes related to the novel you're interested in.