You got an HUGE enthusiast here. Good to see a another likeminded fellow, they're just as rare as this phenomenom.
We were a couple people that was active here on these boards some years ago that frequently talked about this, collected fiction, pics and videos of it. We were a varied group that more or less had an great thing for female bodily matchups, competitive/sensuous women, female asses, well shaped asses and lesbianism. We shared our experiences and thoughts.

Ive been around since my mid teenage all into this "fix idea" that completely turns me on. I am basicly a assman with huge passion for womens asses, but also hints of lesbianism. And I do have encountered and asked a few women if they "ever thought about such things" or if there's a turn on to this, a few completely agreed. Eventhough they are just as rare, there might be a load of ladies around the world that likes assfights or ass-vs-ass matchups. Only that is a great thrill to think of.

Obviously the idea also strucked Lisa and Tasty to pair and match their asses up.

You RingoD asked for more ways of butt-vs-butt contests, and one I know and really like is when two women are back-to-back standing, (knees or on feet), with interlocked arms and tussling their asses together pushing. Also adding an another aspect and move, that if one pulls an advantage of the other in the push, she could manage to lift the other up on her back. So she becomes inferior, only lying and pressed back to back and butt to butt, stretching her back.

Just an example:
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(The blonde beauty is JCMarie, and SHE is a girl that obviously enjoys butt-battles since she has been doing a couple videos with it.