>>27634275Just go with the flow. Have a general idea of where things will lead, and how it will end, before you begin writing.
Always good to start with fluff so your readers can better visualize characters and environments, internal monologues are your choice though.
When you are finished the script, go back and edit/delete/add scenes until you are satisfied with the outcomes. Good smut is a rarity, so don't expect it to be amazing right off the bad. Just like real sex, it takes hard work and dedication for it to have a good result.