Tunking is a looksmaxxing technique where one flosses between their toes with yarn. It’s said to help with foot growth which is genetically linked to one’s height.
When you tuck your penis in under your balls and try and hold it there, typically done in a semi-flaccid state while standing. Seasoned tunkers may be able to tunk as far back as into their ass, having foreskin can greatly assist with this.
I was tunking in the shower and my penis flew out and started smacking against my stomach like a pendulum!
To exchange something for the exact same thing you traded, or to trade something for the same thing you offered as a trade, or to make something that ends up being the exact same as the source material.
Tinking:
To exchange a dollar for a dollar.
To make gold from gold, or buy (the same amount of gold) with the same amount of gold.