You would use this interjection when you see a fine piece of ass. As this girl walks past you, you must lean back and exclaim this this phrase with impeccable timing. This is especially useful after watching a fine lady such as Danielle Conklin pass by.
a word that black kids (and white kids who copy everything black people say) use to sound like a over annunciated word of "damn." Usually used when somethings extremely exciting or calls for an out burst of "DAYUMMM" instead of just damn.
1.DAYUMMMMM tht gurll is fineee as heeellll.
2.DAYUM i just spilled muhh drinkk.