Great, nice pooping action and a fairly good twist. Almost like a demented version of those novels they make (being an unrelated event to the anime/manga). Though I was still hoping you'd also cover Riza's little 'business'. Maybe you could do two mini chapters, one for Riza and another for Sheska (she's second to Winry for me, those glasses make her so cute).
Once more I'll mention the past/present tense hopping, but again it's not that bad. I would say it'd be nice if you played more of Ed and Winry's feelings, like more private thoughts with them and so on.
All in all, a great fiction and very well done. ^__^ *Big thumps up*