"Ok, ok, pen..." then you say: "here you are," and lovingly pat the pen on its head. You walk over to the kitchen sink when it's not looking and pour water into it's lid. Then you mix it with red food colouring.
"It won't notice the difference," you say. "Hopefully. Come here, little penny wenny."
The pen obligingly hops over to you. You unscrew the top and carefully pour in the 'ink', as to not drop a bit : it's that precious. Unfortunately, you are only doing that to pretend it's precious. Really, if you spilt the whole thing down the toilet it wouldn't cost you a cent.
Then you screw the cap back on again and see your pen's reaction. It...