A previous entry had only half of the definition. The Abraham Lincoln is a two-part sex act. First, your girl blows you, and then pulls out and lets you come on her face. Then you pull out some pubic hairs and throw them on her face, then making her resemble Abraham Lincoln's beard.
Then after you've recouped, you bend your girl over and pound her doggiestyle, and right before you come, you say "It's a beautiful day at the theater, Mr. Lincoln!" and then pull out and shoot your load on the back of your girlie's head.
I Abraham Lincolned my girlfriend last night, and she broke up with me.