2. Not cluing in to what a particular conversation is about .
The next person will reply in a humorous tone of voice "pack-a-lunch"
2) (Slang) To be prepared for a long effort
3) (Slang) To wear a false penis, esp. a lesbian/bisexual woman
If he's going to tangle with me, he'd better pack a lunch.
At the lesbian bar, half the women were dressed as men and packing lunches.