You might use the edge-flip algorithm, which flips the top two edges on the cube across from each other.
M U' M U' M U2 M' U' M' U' M' U2
This algorithm ONLY flips those two edges, and leaves the rest of the cube out
i know it may seem long, but if you use your ring fingers for the M's, on a really well lubed/springed
cube this move is very fast