To Throw, kick, or smack a ball or other object with maximum inertia capabilities into the general crotch area of another person, player, or victim.
Exclaiming, "DING!" when an object and crotch connect is optional.
Billy and Julie played crotch ball the other day. Billy kicked the soccer ball at Jullie's crotch 4 times for a total of 8 DINGS(points)!