They always take things literally.
A *cow*culater. I made it up myself, so don't groan at the pun.
Mandel broth Ha ha ha The puns I make up while working as a grocery cashier..
And why doesn't my girlfriend share this impulse?
A toothbrush.
Olive.
Three times - Once when you tell it, once when you explain it, and once when she gets it.