In my view, if a stock is making a run up, it should not be shorted; regardless of the candle formation. The way I see it is that a stock in an uptrend means that the buyers are in control, but a bearish engulfing pattern indicates that sellers have momentarily taken control of the stock, so the combination, overall, would give me mixed messages.
However, a bearish engulfing pattern within a downtrend provides me with 2 separate pieces of evidence that the sellers are in control. The fact that the trend is down means that the sellers are more aggressive than the buyers, and the bearish engulfing pattern means, to me, that the buyers made an attempt to take control of the stock, but were, once again, defeated by the sellers.
This combination does not guarantee anything, but I think it does put the odds in one's favour:
