Sonic Rainboom 

A Rainboom made by rainbow dash in the MLP series.

Rainbow dash made a sonic rainboom to save rarity at the episode 'sonic rainboom'.

Sonic Rainboom by Rainbowsandra June 15, 2016

Double Rainboom 

A Double Rainboom is a fictitious phenomenon invented by the people working at Lfamingo Rich Productions in which a pegasus(a magical horse with wings)flies so fast that they break the sound barrier. at a speed of mach 1 or 2 the pegasus initiates the Double Rainboom and immediately accelerates to around mach 5. this is only the beginning, the pegasus's tail and mane color also determince the color of the resulting circular rainbow that spreads outwards once the first rainboom is achieved. when the pegasus accelerates to around mach 7 which is easier to achieve flying directly downwards using gravity to your advantage, then the first of two rainbooms occurs. from mach 7 to mach 10 in an instant the next rainboom occurs and propells the pegasus performing this so fast that the pegasus actually has a very likely chance of being sent into another dimention completely.

In the Flamingo Rich production Double Rainboom Rainbow Dash drinks a talent inhancing potion and manages to fly fast enough to get flung out of the MLP dimention and into the Powerpuff Girls dimention(which is another show meant for young pre-pubescent girls.

Double Rainboom by Cspinz December 26, 2013

sonic rainboom 

1) When a pegasus pony breaks the sound barrier in flight, resulting in a rainbow and a sonic boom at the same time.

2) The most amazing fucking thing to ever happen on television.

When trying to catch her falling friend, Rainbow Dash unintentionally performed a sonic rainboom.

sonic rainboom by AwesomeSauce42 October 25, 2011

sonic rainboom 

When your banging your partner and then soon you start shoving your penis into her anus, and you try to shove it until it touches her sphincter, and then after minutes of shoving, you cum a painful stream into her anus. Named after the aerial stunt from MLP: FiM.

Last night, dude, I started giving your mother the sonic rainboom and she was like, "OWWW!!! STOP IT!!!!".

sonic rainboom by A Really Bucking Fastard January 17, 2013

Rainboosie 

A gay best friend you think of as a brother or sister. The bond you share is inseparable.
A LGBT boo

"I'm going to visit my rainboosie at a club."
"Going out to party with my rainboosies tonight."

Rainboosie by Ghostdoll July 2, 2020

Rainbowman10guy 

A fat man that eats a lot and spends money only on Fortnite

Person: Damn look at him he’s got so much Vbucks. Other person: he is probably rainbowman10guy

Rainbowman10guy by ItzLambChopz April 13, 2019

Rainboo 

A rainboo is essentially surprise rain, that creeps on you unaware.

I was walking through the park when I was struck by a rainboo

Rainboo by Jimlar May 10, 2010