As a noun it is used to describe a true ladies man, a man far superior to Edward Cullen and other such snitches. Such a man can pleasure a woman in many ways, and will possess unusually large genitalia as well as an unusually long and flexible tongue. He also would possess stunning good looks, obviously.
As a verb it means to give roses or sometimes flowers, most often one red rose.
Did you hear what Joe did? He totally Matt Duncaned that chick.