The act of mentioning any potential fanfic's plot, whether sexual or not, will cause that fanfic to come into being in a publicly accessible location.
Robert: God, can you imagine a story where Jean-Luc Picard and Twilight Sparkle went on an adventure together?
Jean: Stop! Don't invoke Rule 235-- damn it, that story's on fimfiction.net now. "Discord's Prime Directive."
Robert: I'm so sorry.