Just a random idea that came to my mind when I accidentally came across that one pose linked below.
To clarify: this image is NOT intended to imply that Pinkie has, uh, bad hygiene habits. She's Pinkie Pie, remember? What if she can wander around and collect scents like they were, let's say, bottle caps?
She could come across a new scent, use her mystic Pinkie powers to capture its essence, and just wander away. Other than that, she would be pretty much fine with keeping herself clean, I believe. And you could feel those scents only if you were unlucky enough to have that tail pushed right into your face...
--------------- Inkscape SVG file: sta.sh/027bc75nflcl Mostly traced from the show. Original screencap: sta.sh/0oq9i5hnxqi
(S1E15: Feeling Pinkie Keen)
(26.08.2012) Updated into an actual vector. A few details were changed, like Twilight's expression, her body pose, and the length of their legs (they seemed a bit too short). Also, I increased the general thickness of the outlines to make it look more show-wise. Now it looks much better I believe.
--------------- Based on "My Little Pony: Friendship is Magic" by Lauren Faust.