carmalizing his onions

To get someone high on acid in order for them to tell you the truth about something.

"Has he come clean yet? "
"No, but I've been carmalizing his onions for the past three hours. He'll come clean in no time."

lay it like an onion

An idiom which is used when someone is being an idiot.

Wedge: Wheeeyyy!
Vlad: Wedge, just lay it like an onion!

Gone off onion

When you leave an onion in the fridge for too long and it goes moldy and stinky.

The gone off onion tastes like a vampire's breath

French Onion Soup

When someone (or multiple people) shits, pisses and cums in a hot tub.

*Two dudes in a hot-tub*

Liam: I’m going to French onion soup this hot-tub.

Jack: Man please don’t French onion soup this hot-tub.

Liam: no.

*Liam shits pisses and cums with the power and ferocity of 10 suns*

Onion puss puss

Pussy so Stanky that it will make you cry of Tears that are wetter than her stank ass pussy

Guy puts face in her pussy damn that shit stank girl you gotta onion puss puss

peel the onion

The painstaking penetration of an anus without the proper lubrication.

A: Duude, Jane squeeled like a pig last night
B: Whatcha do to her,man. Did ya peel the onion on her?
A: Totally..

know one's onions

to be competent and authoritative in one's work

He really knows his onions when it comes distilling alcohol.(example of know one's onions)