Seibeling 

The act of fantasizing/masurbating about a sexy Professor and becoming either wet or hard during their class and subsequently going home and masturbating about them.

As I listen to my Professor's voice in class, I am seibeling of him with his hand in my pants.

Seibeling by Hot for my teacher February 17, 2008

Younger sibling

A little pest who likes to burst into your room while your doing homework, or playing on your phone. They like to hit you, then like a little bitch, they tell your parents when you hit back. In other words...they are annoying. They are so annoying they make you feel like banging your head against the wall so hard you lose all your brain cells.

You: *on your phone*

Younger sibling: *bursting into your room and runs up to you* Hey!

You: Go away.

Younger sibling: No! *Slaps*

You: *Slaps back*

Younger sibling: ....MOooOOoOoM *ugly sobs*

You: GODDAMNIT *bangs head against the wall*

Younger sibling by Crippled and depressed March 29, 2019

National Slap Your Sibling Day 

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*

National Slap Your Sibling Day by yourveryownmother October 28, 2020

Slap your sibling across their face day! 

On the 1st November, you can slap as little or as many of your siblings across their face

“Hey! It’s national slap your sibling across their face day!”

Slap your sibling across their face day! by Reetusthedinostomper October 26, 2019

Soul Sibling 

A friend who you are very close to and see and talk to almost everyday; it's as if they were your brother or sister; they are like family to you.

Your personalities match perfectly and you get along very well. You can tell them anything and they can tell you anything. Your souls are in sync.

Similar to brother from another mother or sister from another mister but no relatedness is implied.

1) Craig and Danielle are my soul siblings.
2) You see that guy over there, he is my soul sibling.

Soul Sibling by friendsfreak1989 November 6, 2010

Little sibling 

The most fucking annoying piece of shit that walked the face of the earth. Copy’s ur every fucking move.

You are playing COD and u die
Me FUCK
little sibling: FUCK
Then ur mum walks in and grounds u for a month for teaching sibling swears. You see little sibling gripping mums leg and sneering at u.

Little sibling by Maboiasznee November 21, 2019

Sibling 

A creature sent to earth to remind you that your parents are still having sex.

"Dude, congrats on your new sibling!"
"Man, don't remind me! All that means is my parents had sex at least 9 months ago."

Sibling by thedifinerofdefinitions January 12, 2015