1) verb- Drop a glock (or drop the glock, or whatever) has a similar meaning to bust a cap. The word comes from the streets. Gangstas in some areas will tuck or strap a handgun, usually a nine or glock, in their sleeve, up by their shoulder. If a situation arises where a gun is needed, the gangsta can snap his arm in a downward motion, thus freeing the gun and letting it slide down into his/her hand. Now the gangsta is ready to bust a cap.

2) verb- Used as a threat implying that the person is willing to do what the above definition describes.

Commonly used in text messages or social media as a short form for Very Sound Advice.