Not sure how that works, but if it does work it's certainly worth a try. I know that you cant short following an actual sell, but you can on a buy.
The shorting technique that had previously been utilized was following very early buying (which was happening daily at the opening bell), and quickly follow it up with shorting within a few minutes to make it appear that the stock was dropping right out of the gate.
The affect was to depress further buying in low volume situations, and then try to cover at the LOD before it moved back up. The end result was making a few pennies on the short sale.
Once c-ship has ended and the world knows that the GSE's are back in control of $20 billion/year profits, this technique will be suicide.