Cherie I would have to say that with most things in life , as Nikki said there are certain things that are definitely black and white . We all have our likes , dislikes and they are usually set with regards to aspects of Medfet. That said there are areas of greys that come into play when experimenting with new aspects of Medfet . As Nikki said what you discover is that sensations, feeling , attitudes change over time and we adapt to keep thing we find pleasurable and discard we don't.
I also believe that also who is involved , their commitment , attitude and support as well as acceptance helps to further merge and grey the boundaries. So as you can see its quiet a fluid experience and ever changing . I know certain aspects have changed over time in my personal life
I would have to agree with you when you said change one variable and it may go from being pleasurable or accepted to not, as with all things in life be it a fetish/kink or not. Experimenting can be a method to try out new experiences or keep adding to the experience of your particular fetish/kink. As with everything in life , things become boring and dull if we repeat the same sequence , a bit of variety keeps the spice and intrigue alive , be it with new positions, implements, duration , sensitivity , pressure etc.
One important factor to consider , take note of , is fantasy and reality rarely live up to the expectation, the hype. With the term fantasy we often imagine a wondrous, extravagant, unrestrained with imaginative conceptualizing. So by it's nature it tends to idealize a concept which is unattainable by its very nature. That said once you accept this limitation, there is no reason why you can't have a wonderful, enjoyable and satisfying reality .
Hope this helps answer some of you concerns Cherie, but whereas fetish/kinks are concerned don't over complicate or overthink things , just enjoy and accept the experience and you will find your own "grayness" in amongst the "black and white".