stuck knuckle Share definition Flag The sexual act of fingering someone so tight, your knuckle gets stuck. "Dude, did you see that chick? She's so hot!""Yeah, Tommy stuck knuckled her last weekend." stuck knuckle by BenjiBonz October 12, 2013 0 0 Get merch Get the stuck knuckle mug. Buy Now — $32.95 See more merch