Why are these women smiling at me, then turning their backs towards me?

I’m currently on vacation in another city about 1000 miles from where I live. I went to a café for breakfast and while I was waiting on my food, 4 women walked in. 3 were in a group, maybe mid to late 20s, dressed in business attire and the other was an older woman, maybe in her 40s-50s.

When the group of 3 walked in, they all smiled and sat at a table next to me. 2 of them had seats with their backs towards me and the other one was facing me. Every time, the one that was seated facing me got up, she immediately turned her back towards me. She’d stand still for a bit before sitting back down or walking away. Did she want me to look at her butt? Then one of the other 2 was complaining about her butt being so big. All 3 would occasionally glance over to look at me, but not say anything.

When the older woman walked in, she smiled too. After she ordered, she went to sit down on a bench to the right of me. She stuck her butt out and sat down slowly with her back towards me. It was weird.

Did these women find me attractive, were they being disrespectful, or just being silly?

Why are these women smiling at me, then turning their backs towards me?
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