crotch buster (krotch bus-tur) n. A bump in the road–either unavoidable or unexpected–that sends your saddle into your private parts, usually resulting in pain and/or an expletive outburst.
I’m so happy they removed the crotch busters along the bike path! It’s so smooth now!
Friggin frigity flipper flap, that was a crotch buster!
Crotch busters are most commonly observed where two forms of pavement are not properly aligned, as when asphalt meets concrete, or change shape differently according to the temperature. Or when tree roots push pavement up.