Yes, it is.
I'm not referring to the need for Maxis to give any kind of "permission" for you to create such an item.
In order to create a new object for The Sims, you need to A) use a Maxis-supplied utility like The Sims Art Gallery or B) use the Transmogrifier, a third-party program.
The Transmogrifier is your best bet here, because the Art Gallery is the only Maxis-supplied utility to create new objects, and that only makes hangable paintings.
HOWEVER. The Transmogrifier can only "clone" existing objects... which means you can take, say, the Guinea Pig and change his artwork around so that he's a Rabbit. It requires cloning the Pig (which is a fancy way of saying "make a copy of this object") then extracting the image data and animation frames, which Transmogrifier does, so that you can draw new images and compile them back into the object, which bundles all the graphics together with a handy XML-like scripting language.
You CANNOT, however, make that rabbit "do" anything that the Guinea Pig does NOT do; the rabbit will let you play with it, spread disease, and nip your hand just like the object you cloned it from. This means you can't add a Pie Menu item to the Rabbit called "Punt" which will show your Sim treating the bunny like a football, because you couldn't Punt the Pig, and you cloned the rabbit from the pig.
So the Transmogrifier basically lets you create objects that do exactly what the existing objects do. None of which, sadly, include any bondage or tickling behavior.
In order to create an entire new object, like a rack, a set of stocks, or a tickle tool, with entirely new behaviors or in-game effects, you need new artwork, new meshes, new animation skeletons, (easily created by any readily-available art and modelling programs) and (this is the kicker) a way to program the new behavior the item requires into the game. Bluntly, you need the development kit that Maxis used to create their objects. This requires a special proprietary thingamabob called "Edith" and knowledge of the "SimAntics" Scripting language.
Neither of which is available to the general public, to my knowledge. At least, I can't find it on any of the Sims object development sites. The Transmogrifier site mentions it will be released "when it is documented". So who knows.
That is why you need Maxis' help to do something like this. You need their help because they are the only ones with access to Edith and SimAntics. There's simply no other way.
Just a bit of info from your resident game programmer.
