Drop a knuckle Share definition Flag When one performs fellatio and inserts a finger up their ass to enhance or spur an orgasam Drop a knuckle when going down on your girlfriend just before she cums, she will love it! Drop a knuckle by DonnyKidd March 7, 2015 0 0 Get merch Get the Drop a knuckle mug. Buy Now — $32.95 See more merch
