Now regarding actual experience with sinking, I have none. Speaking from a male viewer stand point, ever since discovering the wealth of quicksand/mud videos I have always had a relatively simple taste in scenes. My favorite scenes have always been of actresses in either bikinis or lingerie struggling and sinking slowly in thick clay/mud. Now I feel it may be more common for viewers to (understandably) prefer the "realistic" scenes of women more properly dressed considering the environment as well as the actress sinking quickly rather than slowly, but for me, the quicksand fetish has always been more of a damsel in distress fantasy, or an escape from reality in other words. Call me crazy, but I can't get enough of the simple scenario of an attractive lady that's wearing a sexy bikini or lingerie for no reason who then happens to fall knee deep into quicksand and slowly sink and struggle her way down. I still enjoy the more complex scenes with the actresses wearing different outfits, but the simple stuff is my bread and butter. It really is kinda hard to explain in better words the attraction of this, sorry if my explanation is a tad bit vague.
I hope I was able to bring some insight into one corner of the quicksand fetish. I'm sure many more members will be more than happy to explain and clarify their attraction to different aspects than my own as well. Take care Sarah and I can't wait to see more of your work. Happy sinking!