Plunge a watermelon 

When you lose a large anal bead in somebody's butt and have to fish it out.

I was pleasuring my fuck budy with her string of anal beads when one broke off inside of her. That was the first time I had to plunge a watermelon.

Plunge a watermelon by DaSaltySailinTruthSerum September 3, 2016

Plunge into darkness 

Whenever a man inserts his entire head into a woman's vagina.

Steve: "Hey Mark, I saw you went home with Cindy last night. How did that turn out?"
Mark: "Dude I nearly died last night. She made me take a PLUNGE INTO DARKNESS, I passed out inside of her."

Plunge into darkness by Ragebeard May 11, 2018

Plunge Brothers 

When you and a broham have mad bromance. like this man is as studdly as yourself. Ride together, smash together

Example;

Brandon: bro!
Johnny: what up baby
Brandon: let's bang chicks together and label ourselves Plunge Brothers !

Plunge Brothers by Ezeverlast August 28, 2018

plunge your toilet 

Slang phrase meaning "I want to shove my hard shaft up your ass" aka anal.

Babe, I want to plunge your toilet, so bad tonight.

plunge your toilet by lil_birdy January 3, 2019

Plunge your clunge 

Plunge your clunge is a good phase to use when you want to absolutely rail your significant other

Can I plunge your clunge

Plunge your clunge by FourTwenty6ixtyN9ne November 10, 2020

Plunge Pool 

When you go straight from 2nd base to 4th base.

Brian was excited to try the plunge pool on his honeymoon.

Plunge Pool by Skeletor2727 July 4, 2023

Plunge horse 

A horse at long odds who receives the predominant amount of market money at a late stage in betting and thus ‘plunges’ the price into favouritism or near favouritism.

How many fucking times does your plunge horses have to get rolled before people wake up and realise your a fucking dud!!

Plunge horse by Big_jim420 February 10, 2024