Testicles
noun
You have some gold balls. What balls are more important than any other balls, at least for a dude? That would be his testicles.
This word came about because tanuki scrotum skin would be used to pound down gold into sheets. Tanuki scrotums are apparently very good at this because they are very strong and very flexible. Strange, yeah? That's why Gold balls = testicles.
As you might have guessed, this word is slang and you'll probably want to avoid using it at the doctor's! It's a comical word that is used in casual situations.
This word uses the on'yomi for 金 and the kun'yomi for 玉. If you know the readings of your kanji, you'll know how to read this as well.
自分の金玉
one's own testicles
タヌキの金玉
a raccoon dog's testicles
それは金玉ではありません。
That is not a testicle.
自分の金玉が気に入ってます。
I'm satisfied with my testicles.
金玉は男の人の体の中でも大切なパーツの一つです。
Testicles are one of the most important parts of a man's body.