It comes from the spanish word "maceta" which means "vase or pot for flowers and plants". The act of planting would be "macetear", which can be a synonym for jerking off in spanish. And so, someone who jerks off a lot can be called "macetein".
n. A screenshot fabricated by a company to misrepresent the graphics of a game; a combination of the wordsbullshit and screenshot.
Originated from Penny Arcade, a popular gaming webcomic.
-Have you seen Madden 2006 for the Xbox 360? The graphics are gonna be awesome!
-Dude, the Madden 2006 images they showed at E3 were bullshots. It doesn't look nearly as good as they said.