peaky dome Share definition Flag When you have a boner and you're hiding it under you're belt and the tip of your penis is showing through the top of your pants. Grim tried to hide his cock in his belt but ended up with a peaky dome that everyone could see. peaky dome by Greasy Sliders July 21, 2015 0 0 Get merch Get the peaky dome mug. Buy Now — $32.95 See more merch