When an upper classman (such as a junior or a senior) adopts the new addition to the school, a freshman. Pet freshmans are a joy to have and can help you through sticky situations. Upper classman usually argue over who's pet freshman is better.
ex1
Junior (Miranda): CALLIE, MY AMAZING PET-FRESHMAN I HOPE THIS COUNTS AS AN EXTRA-AWESOME BIRTHDAY GIFT! I mean getting put in an example for urban dictionary? whats more badass then that?
Pet-Freshman (Callie): OMG MIRANDA YOU'RE SUCH AN AWESOME JUNIOR ITS RIDICULOUS! THANK YOU SOOOO MUCH!

ex2
Senior (Michael): Man, my stupid pet freshman blows. i should have chosen someone cool like Callie.
Pet-Freshman (Conor): But Michael i tried so-ooo penny! *runs away*

ex3
Junior/Senior: Pet Freshman! Go kill the other pet freshman!
Pet Freshman: KAH-MAY-HA-MAY-HAAAA! *pet freshman dies*
by mp054 March 19, 2010
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The day of December 3rd, when all upper-classmen (high school & college) adopt a Freshman, as if they were a pet at the homeless shelter, and pet them, like a pet bunny, but more domesticated.
John: hey man, you gonna attend Pet a Freshman Day?

Mark: yea man, I even bought a nice little cage with a water bottle in it.

John: that's sick dawg.
by magoffin_lad9 November 14, 2010
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Day that takes place on the first Friday of December that is dedicated to "making freshman feel more inferior than they already are" by petting them in a loving, non-harmful way. The best petting occurs with the little ones, getting a solid pet right on their heads. It is made even better by shouting "You're so adorable!" in a high falsetto during the pet.
Rob: Yo dude, are you celebrating Pet a Freshman Day this year???

Alex: OF COURSE! I pet freshman all the time, now we can all celebrate their adorable awkwardness together!
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