An erogenous zone is a patch of skin or tissue that lights up sexually when touched. Genitals top most lists. Necks, ears, inner wrists, lower backs, and the backs of knees make the extended map. The map is individual. A place that melts one person can tickle another into a bad mood.

Density of nerve endings explains some of this. Attention explains the rest. A throat becomes erogenous after someone has kissed it with intent for a month. Context can also shut a zone down: a stomach after a cruel comment will not want a hand.

Ask and watch. Goosebumps and a lean-in are data. A flinch is data too. Moving slowly across a new area beats landing on it like a punchline.

Feet belong on some maps and not others. Fetish is when the zone becomes the main event. Ordinary erogenous life is broader and quieter.