Well, yes, that pen dust is affecting you. We have been talking about that. However, that aside, you raise a good question.
The tool is used for putting the sleeve into the call from the mouth end. And then, after the sleeve is secured in the call, usually with a drop or two of CA, the tool is then used to push the little tone board in, again from the mouth end. Later, when the tone board develops problems, or you just want change voices, you use the tool from the exhaust end to push the tone board out.
That is the reason that the 1/4" tool, with a step sanded into it, as shown in the picture, works so well. The larger end can be used for pushing the sleeve in and also for pushing the tone board in. Then the small, sanded end can be inserted into the sleeve for removal of the tone board.
Now, lets get back to that pen dust and what it is doing to that brain of yours! ;D