Pidgeon holeing is when you close out all numbers except the one number your opponent has closed. Example, your opponent closes and points 20's. You close and point 19's but instead of taking a stab at 20's when you want to make a run for it you close 18's and so on so forth. It is a similar strategy to closing bulls early. In that it really effects their mental game. The advantage to this is that you don't have to move as far ahead point wise before making a move because every mark on an empty number is essentially a point. I don't think I'm doing a very good job of explaining haha. That's pretty much the gist of it but please note it's not as effective against better players and if they realize what you're doing you may have to switch strategy.