It's likely a joke fetish as of now (cannot find anything like that), however, with enough time, someone might either do it for real, or draw it.
A more "vanilla" variant of just inserting a traffic cone into the anus (no other nastiness with the toilet pump) is uncommon but exists in both real and hentai form. MMD artist YasaiPantsuu (if I remember correctly) made some videos of a 3D anime girl inserting a traffic cone in their series of anal expansion stuff. In real life however, don't expect a large traffic cone to be fully inserted (not even the icium could handle it).
just so I can be sure to avoid it
Don't be shy! It's okay to have weird fetishes, even if they're not very realistic, just make sure you're not overstepping other people's boundaries (don't force fetishes on people they don't like, don't try unrealistic things in real life, and so on).