Library card 

A metaphorical card that one loses upon engaging in sexual intercourse in the library.

Kate took John's library card in the stacks last night!

Library card by lbeesntdeirx February 19, 2013

library card 

a plastic card that enables one to have fun in circumstances related to the dewey decimal system

Because having fun isn't hard, when you've got a library card!

library card by Arthur Reid January 4, 2012

Louisiana library card 

When your parents are in the next room so you and your sister go to pound town quietly

Brother: looks like we might have to pull the ole' Louisiana library card today, mom and dad are home *insert a subtle "Yee yee"*

Sister: mom and dad died in the crash 8 years ago brother...you gotta let it go..

Louisiana library card by Connorbrown3993 January 12, 2019