I want that device to help my constipation (eek). I've seen pics looks a bit erm I dunno but not fun springs to mind.
My continence nurse mentioned the anal plug (what rebecca called an anal tampon) to me even though my issue is the opposite. Is this a sudden prob (eg past few days) or one you've had for a few weeks? As it could be something you've been taking, meds or food. Either way I would either give your continence nurse a call or your GP if s/he's a bit hard to get a hold of.
I hope everything goes well for you.