When you want to have sexual intercourse with that ass. (similar to "tap that ass") but the ass is so good that you can rap to it while tapping it.
"Christy has a nice ass. I would rap that ass."
On fat ass day you WILL get a phat ass.
This is a holiday americans celebrate every april 12th with joy. This originated in 400 b.c when the greek gods gave eachother hot steamy lap dances and one of them said "well goddamn u have a phat ass"
Refumiuswechelfegalteanwearq: its phat ass day
You: yay
When Matt Wagg takes a shit in Metro and it fucking smells like absolute shit
Matt took a shit and smells like a rotten ass wagg