A day to give your sibling(s) some love! Give them a gift or simply just tell them you appreciate them.
Happy Siblings Day bro I got you a gift
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National oldest sibling day is a day to be thankful for the oldest sibling for basically being a 3rd parent, they sacrificed many things for the young ones, and most of all, get yelled at the most.

National oldest sibling day takes place on July 15th
Guy 1: I hate my older brother!
Guy 2: Be nice bro! It’s national oldest sibling day
by abiban74 October 16, 2019
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A national holiday where you can slap your siblings! It’s a wonderful day.
“Hey, sister.”
“Hey, what’s up
“Happy national slap your sibling day!”
“Wha-“
*slaps*
by yourveryownmother October 28, 2020
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When it hits the 16th of November, don't forget about "National Slap Your Sibling Day".

Stepsiblings included.
Have a slapping time on the 16th! A day to mark in your calendar.
"Ow, why did you hit me?"
"It's National Slap Your Sibling Day!"
by UrbanWriter123 November 16, 2021
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