I'm not sure if that would fulfill the story part of your requirements, but here's my thoughts (if you're still open!):
A picture of Thrashy, threateningly having his tail lifted and presenting his rear. He was probably threatened by a mischievous fox, although the evil smirk on Thrashy's face (head turned around and looking at the viewer) suggests that he miiiight have lifted his tail more for the fun of threatening others than to defend himself from an actual threat.
It could include a scared fox as a second character, but doesn't have to. I guess the mimics would tell the "story" or situation better than the actual pose.
I'd prefer SFW, so no 'specific details' for Thrashy's rear. Also no actual spraying is happening. He's not
that evil ^^
Let me know if that sounds fun for you to draw :)
I don't really have a ref, but I usually use this picture:
A wonderful Christmas surprise gift from cosmicfs. . Thank you so much for this awesome picture, it's perfect! :)
www.furaffinity.net
Basically, he wears a blue denim vest over a black shirt. And I guess in this case he wouldn't be wearing pants (which actually he doesn't on most pictures I have of him) ^^