Hip-hop and gangster cultural fashion: Wearing one's pants below the level of the waist, sometimes below the level of the buttocks, with one's boxer shorts showing. The style may date back to around 1989.
The origin of this originally young, urban, black style is unknown. A commonly accepted origin theory was that
is was an outgrowth of prisons, where inmates' clothing was often too large and sometimes no belts were allowed.
It may be related to skateboard/
snowboard fashion.
At least one scholar thinks there is a
tie-in with African culture.
There is also some evidence that a male showing his underwear-covered buttocks in prison was, at one point, linked to a desire for sex, or a mark that a
prisoner was "owned" by another prisoner, sexually. Whether this kind of showing one's buttocks has any relation to sagging is unclear.
Some areas have begun to
outlaw this style recently (2011). Apparently the
objection is the amount of underwear shown.
Example:
He was sagging, hitching up his pants,
shuffling down the street, with a swagger. He was really
busting a major
sag.