I NEVER SAG. BOO!
Straight sagging, where the jeans/shorts are worn low all the way round, usually just below the hips, but not so low as the genital area, usually held up with a belt.
Butt sagging, where the jeans/shorts are pulled down at the rear only, sitting just below the butt.
Extreme sagging, where as much of the underwear as possible is revealed, showing the entire butt and some or all of the genital area, often with jeans/shorts so loose that they are in constant danger of dropping right down.
Double sagging, where one, two or three pairs of shorts/pants are worn, with each layer revealing the layer beneath. This allows the overall sag to be much lower, and therefore more impressive.
Freeball sagging, although not true "sagging", which requires underwear to be shown, is often seen on beaches, where boardshorts or trunks are worn particularly low, without underwear
Other sagger, explain in message area.