The immovable rod doesn't move without a very large amount of force. We know this.
One of my players is asking if the button on the immovable rod has to be pressed and then released to activate it, or just pressed down to activate it. There's no RAW answer for this, so I'm looking for a rules as interpreted answer for it.
He's wondering if he can slam the button against a wall and stick the rod there, where the button's permanently pressed so as no one can move it again (outside of destroying the wall and then pressing the button, which would take far more time). Is this possible?
Alternately, does it repeatedly activate and then deactivate until the button's released, causing it to fall to the floor?
The situation we ended the session where my characters are being chased by evil jailers. They've been through a very long portion of the dungeon, and just ran into a cell and locked themselves in. Well, the jailers have keys. The party wanted to place the button end of the immovable rod against the back of the cage to hold the door shut effectively locking themselves in. When they get done with their long rest, the character with the robe of useful items is going to use a window patch to remove a large portion of the door behind the gate, letting them out.
If they just press the button and affix the rod to the door, the enemy can reach through and deactivate the rod and open the door, same with sideways.
Is this a DM discretion question, or is there any direction on how this would work?