The act of defecating into another’s rectum.
The route of the phrase originates from prison slang as the act is often used as an initiation or power assertion within the pecking order of inmates.

I box dumped him and he now answers as my bitch.
by Jonnieboy February 12, 2008
Get the Box Dump mug.
The act of a male delicately licking the vagina of a female while she is defecating, preferably log-type shit but explosive works as well.
"Dude I totally gave Tiffany a dump box the other night. It was awesome!"

"I love when he does a dump box on me."
by Tiff-Steph January 23, 2009
Get the dump box mug.
When a girl gets eaten out while sitting on the toilet taking a dump.
Tiffany totally got a dump box from Tom last night!
by Tgibby January 23, 2009
Get the Dump box mug.
When you have a plethora of items in your pocket, and they all dump out over a period of time.
Me: hey you dropped more shit!
You: ah jeez, look at me being a McDonald's Dump Box again!
by Chaalsballs October 6, 2019
Get the McDonald's Dump Box mug.