Lately I've focused more on finding submissives on sugar sites. And I noticed that even if a bigger gal doesn't initially mention being submissive, she'll tend to hint at it. So my unscientific sampling suggested that bigger gals were more likely to be submissive than other gals. Now I find a scientific paper that while not mentioning sex at all in any aspect, does indicate that people of girth have a specific brain difference involving reward and pleasure.
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BDSM is all about rewards and pleasure. The punishments only serve to heighten the anticipation of the rewards.
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So it looks like there is a plausible scientific reason to believe that the larger gals are more open to BDSM. (This may go for big guys too, but that's not really my area of interest.)
I had a sub mistress for 12 years. She was a size 2 or smaller, 34c natural breasts. She would get incredibly wet when I whipped her ass or breasts. Whipping her back didn’t do much for her.
Took her in a g string bottom to both South Beach and Desire resort walking along the beach with her reddened welted ass, topless and her pierced nipples. Had great sex after showing her off. We also played on my lake boat in coves and guys would come over in their boats and watch while I sat on the back cushion. L would lay on her chest, suck me while I whipped her.
Could never had done or enjoyed if she was any bigger.
Pal, you should probably not overthink this type of stuff. Being fat or skinny has nothing to do with it, other than larger gals sometimes have to be more game in all areas in order to better please a client.