Need help finding a story from a while back!!!!!!

Story by Chadwickster

Like the title says I need help finding a story, it has been a few years since I've read it and it keeps popping into my mind every now and then, but it basically is a story about some kind of parasite/spore that infects a boy, his sister and their dogs and makes their penises huge and his sister to grow one. I know it is vague and maybe not even around anymore, but I'd really like to read this story again, if anyone knows anything about it or even has a lead or two, I'd really appreciate any help!