It's often used to describe someone who is strutting their stuff, feeling confident and stylish.
Here are some examples:
* "The model sashayed down the runway in a dazzling gown."
* "She sashayed into the party, drawing all eyes to her."
* "The drag queens sashayed their way to the stage."
It's worth noting that "sashay" is a more recent word and gained popularity in the late 20th century.