(1) Man I was so mashup yesterday after all them beers. I was well caned
(2) Jeez, he looked so mashup after they caned his ass.
(3) The track 'A Stroke of Genie-us', is a mashup of Christina Aguilera's "Genie in a bottle" with The Strokes, as is 'Get Your Bootleg On', which is a mashup of a Missy Elliot track (Get ur Freak on) with Eminem's "Without Me".
For definition (1) mashup is a synonym of one meaning of caned, along the lines of being very drunk or stoned, whereas for definition (2), caned means beaten.
Definition (3) is also a synonym for a type of music also known as bastard pop, cut-ups or blends.