The Tickle Stick is an item that Duster keeps. It is one of the six legendary Thief Tools. This can only be used in Battle, and can never be used outside on the World Map.
 How to Obtain
You can only find this item in Wess's basement. That is where you will find all of the other Thief Tools as well.
This item can only be used in battle. When you click on it, the targeted enemies defense will go down. Depending on the enemy, this might only happen once. That is the most common thing. It will usually take about 6 defense down for a weak enemy, and 20 for a strong enemy. It keeps the stats down until the enemy raises Defense again using some move.
The Tickle Stick only appear in Mother 3.