“I’ve never done any original writing” literally everything you post that isn’t reblogging, copying and pasting, or otherwise reproducing somebody else’s content is original writing.
Like, I’m not saying it would be a good idea to respond to a request for samples of your original writing by providing a link to your 3 AM musings about whether Waluigi has a foot fetish, but if you did, technically you would have furnished precisely what was asked for.
There are people in this post’s notes RPing as Waluigi’s bitter ex-husband.
This also qualifies as original writing.