Cyrus,

That would work best with a black background. Otherwise both sets of arms would have an exposure of a light background added to them, while the body would not.

Not any easier, but you could also "paint" with light...Model with a dark background with a good full exposure of whole body, then turn off all lights and open lens. Hand-hold a flash or other light to expose just an arm, then the other arm...aiming the light as not to give any more exposure to the body

Vaughn