It's a rather strange and unclear statement. It could potentially be a very personal or fictional story about a son having some sort of positive or perhaps inappropriate reaction to someone's sexy legs. But without more context, it's hard to say exactly.
There could be various stories related to moms' sexy legs. Maybe it could be about a mom who was a dancer in her youth and her legs were her most charming feature. Her legs carried her through many beautiful dance routines, and she has some interesting memories associated with her legs from those days.
Well, it could be a story about a family trip to the lake. Maybe your mom looks really great in her swimsuit and is having a wonderful time by the lake, enjoying the sun and the water.
In the story, mom massaging legs can relieve pain. If someone has been on their feet all day or has some minor leg injuries, the massage can soothe the muscles.
If we assume it's a positive family - based story, perhaps it could be that a son, in a very innocent way, likes the stories his mother tells while she's wearing a nice dress that shows her legs. And he associates the beauty of her legs with the warmth of the story - telling.
Your mom might be enjoying the peacefulness of the lake. She could be taking a walk along the lakeside, breathing in the fresh air and just being in the moment. It's a story about her finding tranquility at the lake.
Gracefulness is often a characteristic. For example, in ballet stories, the dancers' legs move with such fluidity that it's considered sexy. Their legs seem to float as they perform difficult moves.
In a movie, there was a character with sexy legs. She was a spy, and her legs were not only beautiful but also strong. She used her long legs to run across rooftops and kick bad guys. Her legs were both an aesthetic asset and a tool for her dangerous missions.