I usually see this method in use when one ally comes across another in the process of taking a pill and joins in, taking some of the shots so the first player can continue firing.
As has been stated in other guides, this method of pill taking is fast and difficult to counter. Using the fact that a pillbox will shoot at the nearest enemy, one player draws fire while the other shoots and kills the pillbox. Usually this technique is done with walls between the target pill and the decoy tank. A skillful player can build the next wall she will hide behind as the current barrier is disintegrated. If you don't have the time (or the builder) to build barrier walls, you can use available trees, enemy tanks, or your dexterity to avoid pill fire.
It is possible to decoy a pill without using any barriers, but the decoy tank will probably die. Just elude the shots from the target pill as well as you can by driving up, down, and in circles (not necessarily in that order). The shooting tank should survive with minimal damage.
Never use one of your pills as a barrier to decoy another pill unless you have the area very well guarded. A single mistake can destroy pills, builders and egos. For example, in a recent 2x2, I saw my enemies using one of their pills as a barrier to decoy mine. I crept in from the north, and started firing at their pill as soon as it was dead, killing both their builders. They stopped shooting at my dead pill and ran in to pick both up; I fixed my pill and killed both of them.
With practice and a good setup, it is possible to take more than one pill using the decoy method:
Once again, the possibilities are too many to describe in detail. You will eventually come across practically any setup you can imagine. Don't hesitate to get creative . . . you can take out more than two targets by having the shooter pause while the angry target pill follows a decoy tank and shoots through multiple pills.
The biggest difficulty with decoying is communication between allies. Some boloers who've played together for a while can predict their ally's next move and position themselves accordingly. In the beginning, however, you'll have to send some messages back and forth. If you really want to get organized, try developing a code to minimize typing: "ids" = "I decoy to the south," "ys" = "You shoot," etc.
Remember: