1) n. radical skateboarding move in which the rider leaps over an animal while the board runs under the animal. Care should be taken that the animal is not particularly skittish. By extension "milk the steel goat" is the same move but a car is employed instead of an animal.
2) v. sexual euphemism.
Yo! Dude! Check out the Great Dane! Time for a milk the goat! Wanna watch?