Yours are small! - How much shoving can they do.... Gidget can take up the WHOLE bed, and the cat weighs 20 pounds.
You forget that kitties have CLAWS . . . ours insinuate themselves between us and push us apart. If nobody moves, out come the claws < ooch! ooch! > . . . you wake up with just one corner of the sheet, with three cats in the middle of the bed luxuriating in four pillows, a comforter, and a duvet . . .