Usually, I have some idea of the elements I want to include in my story, and then I think up a situation that could plausibly accomodate all of those elements and write around it. My experience is probably skewed since I've only written a few things and they've all been in a How Would I Inflate You thread, but it works for me.
I suggest taking requests without any real catch. Don't say "female inflation only, no popping," just roll with what people give you, adapt and get creative. It'll make you put some thought into your settings and circumstances to accomodate things you aren't used to. Maybe it'll break you out of your slump.
Maybe you could even make a How Would I Inflate You thread.
Hmm. For me, I try to think of the how first. How did the girl get inflated, and work your way backwards. Or what was their goal in the expansion? Accident, fun, on purpose, for someone else, for themselves, that kinda thing.
That normaly helps me, but what also helps is having a good character in mind. It's hard to progress the story when you don't know what the character would do, but if you know how the character would act in most situations, you can more or less wind them up and let them go.
Anywho, that's how I try to write, hope it helps!
No, I would not want to live in a world without dragons, as I would not want to live in a world without magic, for that is a world without mystery, and that is a world without faith.