If you are concerned about how you write a user story, you have missed the entire point.
A user story is a little card that reminds us of all the actual conversations we’re currently actually having.
If the words "bathtub farting" are enough for the team to actually converse about what they signify, they’re enough for what they’re for. The very first step you take that’s away from "user story is a marker" is the road back to the command & control we were trying to get past.
Think of it as a monopoly piece, like the tophat or the racecar. Stop thinking of it as a document or artifact in any other sense. Do you want a document or artifact? Go to it. But don’t think of that as a user story. That’s something different.
Actual working agility is fundamentally reliant on f-squared d-squared:
Frequent, Focused, Direct, Dialogue.
Nothing. NO THING. NOTHING WHATSOEVER, can replace that or improve upon it.