heya, just a heads up that we generally don't start new threads here without some discussion in the community forum first. there is often a thread up and running where "new" ideas are already being discussed and if there isn't other posters will express their interest (or not) in starting a new one and where it would fit in best. this really helps the boards stay as tidy and easy to peruse as possible, this is unique to bust as far as i know and it works really well here.
so, you may get more responses if you post your query in the general sex thread, the bdsm thread, or the acting out fantasies thread. i know that i participated in a discussion about fisting somewhere long ago but can't for the life of me remember where, it was probably the general sex thread here