The Repellent Stick is a simple wooden stick with mole rat repellent on it. The stick is exceptionally effective against mole rats, as one hit causes an allergic reaction on mole rats, causing their bodies to smoke and their heads to explode in five seconds, while a second hit will cause the explosion to happen instantly. This is probably due to the stick triggering the 'genetic kill switch' put in the mole rat species during their genetic engineering. Do not be fooled by what Moira says when you first get this stick, as it's an experiment gone wrong. Moira will exclaim "Poor little mole ratties!" when she realizes it does more than chasing the mole rats away.
If you use the stick on any other creature other than a mole rat, it will still cause the "smoking" effect, though it won't cause them to explode.
Upon completing the mole rat portion of the Wasteland Survival Guide quest, if the optional objective of using the repellent on seven more mole rats is fulfilled, the player is able to keep the Repellent Stick for future use. If the optional objective is not fulfilled, or if the quest is completed with a speech-based lie, Moira takes back the stick but will sell it to you from that point on, meaning you can still have it permanently if you accidentally or intentionally did the bare minimum. If in the future you don't have the Repellent Stick and you want it, it can be found by lock-picking the desk upstairs (hard). Be careful while doing this, since if you take it this way it may not be taken out of your inventory. It will be considered a quest item.
The repellent effect will not register if you incidentally occur instant kills of the mole rat, such as through the sneak attacks afforded by the Chinese stealth armor or Stealth Boy. You will not get credit toward the completion of the quest unless the repellent has the chance to work on each mole rat before they expire. So, when using this weapon to complete the Wasteland Survival Guide quest, do not use sneak attacks to kill the mole rats.
Because it is a quest item, if you convince Moira Brown to give up on the book, buy it back from her, or pick the lock on her desk and take it after completing the quest, you are unable to drop it. To drop it, open the console and type "player.removeitem 0002D3B7 1"