Don't look, uh, "down the pipe" when inspecting her fullness, my first tip : )
Urates or hard poop can create a cork at the end there, and keep things stopped up for a while. Once it pops, it will be a blast off.
We would manually massage that out over a trash can (watch your pants! and your eyes!) but a warm soak for an hour should also help relax her, and probably get things moving.