[Sangetsu]

"Sexy" can be used to describe a person, a dress or bathing suit, or even a car. "Erotic" is more of a description of something happening, like an erotic dance, eating something in an erotic way, or even an erotic song. A swinger's club may have an erotic atmosphere, using colors, lights, and music which try to encourage an erotic mood (don't ask me how I know this).