My testicles sting.
I'm sure that my testicles are working twice as hard as the other mens'.
The surgery to make testicles gold in color is fully booked for the next six months.
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.
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.