To low ride is to wear your trousers(pants) low down, usually around the upper legs. Underpants are usually visible, but often long T-Shirts are used to hide it.
This term is used when a fucking douche bag wears their bottoms around their fucking ass. Originally, low-riding whilst in jail meant that you were 'keen' for a 'butt fuck'. Low-riding is highly common amongst gay fuck tards.