Chest hair on men, which is allowed to grow without shaving at the top of the chest (in any of various shapes), and shaved clean from well above the nipples down to the waistline.
A chestache allows a manly appearance in a partially unbuttoned shirt, but with a cleaner appearance below the chest whilst shirtless.
"I like his chestache, but it sure gives him a weird tan line."
"I love running my fingers through his chestache."
"His handlebar chestache is oddly appealing, but I wonder how much wax it takes to do that"
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.