shaking his own hand

A somewhat polite term for masturbation

"I opened up the bathroom door and Billy was in there, you know... shaking his own hand..."

Own goal

Changing your own news descriptor from “alleged rapist” to “actual rapist”.

The verdict on actual rapist, Bruce Lehrmann’s two counts of rape in Toowoomba, Queensland have yet to be passed down. (Example for “own goal”)

polish your own pedestal

To engage in excessively narcisisstic/vain speech or behavior.

When you polish your own pedestal, you do a fine job of letting the world know you think you're cooler than you are.

Thomas is normally a humble guy, but after a few drinks he really starts polishing his own pedestal about what a great Scrabble player he is.

Mind Your Own Business

Something alot of people cannot do
Another word for "leave me alone" and/or "You shouldn't be involved in this"

Person: "what are you talking about?"

Person 2: "its nothing, mind your own business"

Pooped in his own hand

An action that backfired horribly
Karma

"Principal Hugh.J added a rule that eating isnt allowed in the classes, so everyone ate in the school halls!
Geez, he pooped in his own hand, did he?

Owning a PC

An expensive way of getting no bitches

Did you hear about Logan owning a PC? Bro gets no bitches

Certified pre-owned child

A certified pre-owned child is a step child

Person a: Hey, I didn't know you had kids?
Person b: Hey

Yeah, this is my certified pre-owned child from my new marriage