1 definition by Justin George Mitchell III
The sexual maneuver in which you cum into somebody's butt hole, lick it along the crack like your sealing an envelope, push the cheeks together so it's officially sealed, and then stamp it by giving the ass cheek a hicky.
"So, Tom and I were pioneering the Postage Stamp the other day and I wasn't able to defecate for almost four business days."
by Justin George Mitchell III March 26, 2008