For a man, it means to have the pube hair shaved right above the penis only leaving some on both sides and on the testicles. It should resemble Honest Abe's beard.
For a woman, it means to also shave the pubic hair right on top of the vagina and leave the sides and gooch area untouched.
What are you talking about I'm not a real American!? My Pube Lincoln begs to differ!