Reading Slug

L2 (7yrs old) triumphantly, pushing back his empty cereal bowl: The reading slug is done!
Me: The reading slug?
L2: The reading slug!
Me: What’s a reading slug?
L2: Didn’t you say that one of your sisters was a reading slug and you tried to coax her outside to play with you but she just wanted to read?
Me: Ahh… a bookworm!