This writing prompt is pretty simple. You can take it in any direction you want. Your response could be a poem, non-fiction, flash fiction, or fiction.
Just take the Phrase “We stayed up all night” and make it the first sentence of your piece.
Now the nice thing about a phrase like this is that it jump starts your creativity but it is also very open ended. Different people think of different things when they hear a phrase like that.
I might think of an all night art walk and someone else might think of a romance. Another persons approach could be a sci-fi story where it is unusual to be awake during the day.
However you approach this, have fun writing this story.