To rob or steal quickly in an inner city- usually accompanied by an unnecessary beating. The act of drapsing someone can be a planned ambush attack or an opportunistic hit.
My man Neil had his phone snatched when he was out walking and gave chase (with the help of a supposedly helpful passer-by, who said he knew of the offender). The chase led into a wooded area of a park...but when they caught up with thief, the sitution turned poor for my man as the "helpful" passer-by turned on him. Others poorly emerged from nearby bushes and proceeded to drapes my man of funds and his watch whilst administating a needless beating.
To drag or forcibly remove someone from where they are, usually a vehicle or a chair. Usually followed by a par of some sort, generally the removal of ones belongings, although being drapes'd is a par in its own right.
Made popular by Tempa T in song Next Hype.
"DRAPES! GET OUT THE CAR!"
"Man went toilet and came back and one fossy was in my seat. So obviously I had to drapes man."