1. The act of carrying a firearm on
one's person.
2. When a person is well-endowed.
Male: Used when referring to a man who has a large penis. Female: Used when referring to a
woman who has large and shapely breasts and/or a large and shapely ass.
"
Girl, did you fuck him? Is he packin
heat?"
"That girl is stacked up, she's packin
heat."