Well, it sort of depends on what you're trying to write and who your audience is. Sure, there are a lot of horny souls that want to have action from the first paragraph. Does that fit with the story you're trying to write? Remember that it will be your name on the posted story.

If you think the story is a slow starter put that warning at the beginning. Or, you can always start with a teaser in the first paragraph to set the hook before setting the scene.

In most of my stories, the sex doesn't usually happen before the second or third chapter. There may be humiliation earlier but I do think that there needs to be time to develop the characters. In my mind, much of D/s is mental. It is hard to see that if your readers haven't gotten some backstory before you get into the action.