When a woman's nipples are obviously erect. Usually humorously called to attention.
"Honey, your headlights are on."
by tradesman April 1, 2003
When a woman isn't wearing a bra.
I saw this girl at Farmers tonight... Her headlights were on.
by Joe Burns November 20, 2001
seeing a womans nipples through a see through shirt
her headlights were shining through her shirt
by handle August 15, 2003
When you can see a girl's nipples through her shirt, occurring most often on rainy or cold days
(rain falling outside)
Ben: Do you know what this rain means?
Paul: No, What?
Ben: Some girls will have their headlights on today.
by Sirk10 April 21, 2008
The visible outline of a woman's nipples especially when they are erect. Erection can occur due to the change or drop of weather or temperature in an environment, sexual excitation or constant friction. This appearance may get a lot of men aroused.
"girl, I can see your headlights", "look at her headlights", "Are you cold, because I can see your headlights?"
by nelle D. April 26, 2013