Stocks have maintained altitude since Wednesday’s steep short-covering rally, but they’ll need to do better than that to avoid a plunge over the next day or two. Buying by nervous bears is the only source of buoyancy right now, but unless shorts are kept under constant pressure, the stock market is in danger of relapsing to recent lows. One implication is that a slow Friday could produce a precipitous slide in the final hour. This would be the opposite of what we’ve seen throughout the bull market, when it became habitual for DaBoyz to “run ’em up” into the close.