Roger pretends to be Jeff’s imaginary friend, so he can freely roam naked around the house with no disguise.
But when big-mouth Jeff figures out that Roger is an alien, Stan issues an ultimatum: either Roger or Jeff must be killed immediately.
Meanwhile, Steve becomes insecure about the shape of his rear end
Episode number: 8x12 Production Number: 7AJN12 Airdate: Sunday February 17th, 2013 Network: FOX
Steve is upset that his bottom is shapeless but in Why Can't We Be Friends, Stan makes a comment about how lucky Steve is to have his mother's butt, certainly implying that Steve has a shapely rear end.
Also, in Season Four's 1600 Candles he proudly shows off his rear after he tells Lisa Silver to watch him walk away.