Thats my favorite kind of story too!!
Off the top of my head, cant think of many, but as they come up, Ill let you know! I think theres not enough "hose in mouth" stories anymore.
Naked Balloon, (explosion), Nanotech pneumatics (explosion sort of implied)
Naked Balloon was the one I was trying to remember. An homage to the inflation/bursting scene in one of the Naked Gun movies.
in the adultinflationwriters group you may also find these kind of stories, and the kaboomstoryannex. In adultinflation, theres a story by Pongo called Working Girl. Involves a hose, a guy living his sexual fantasy, but she inflates against her will. You may want to check that.
Sorry its not exactly a mischievous inflator out to iinflate someone they dislike, but its something ^^
If you like torture inflation I have a site:
http:sapphicstories.blogspot.com
Read Leena Lanka. That seems to be popular with the fans.
I believe the story you may be looking for is called "Distended Rivalry" and I'm pretty sure its on here somewhere.