failcock Share definition Flag A male's sexual failure in a certain sitiuation. Most likely due to the inability during that particular time to maintain an erection, or fully experience a sexual sitituation. Yeah I kind failcocked last night, drank way to much.A Jerry try not to failcock it tonight. failcock by Zamberlin July 23, 2011 0 0 Get merch Get the failcock mug. Buy Now — $32.95 See more merch