Used in context when a girl wears a low-cut top to show off her cleavage. Also a double entendre due the double meaning of the word "drop". As in "drop" the f-bomb or "drop" her top.
Man, did you seeKellytoday??? She really dropped a cleave!
This typically consists of a piece of cloth being tied over the partner's mouth, and is pulled between his/her teeth. A thick scarf is used to hold his/her mouth open, much like a ball gag.
she locked him in a pair of furryhandcuffs and clenched a cleave gag between his teeth