It comes from a classic Fandom_Wank thingie that exploded. _redpanda_ would have the links to the entire wankfest.

But to recap: someone claimed that people were stealing her LotR artwork that she worked on herself and others realized that what she was posting wasn't original sketches but Photoshop-filtered stuff. The "pastede on yay!" comment came about when she claimed that Dom had visited her room.