Statistics from the U.S. Census Bureau indicate that 11.9% of all adult American males are known by the nickname "Mad Dog," while the remaining 88.1% have a friend nicknamed "Mad Dog."  We know these figures are correct because if you add them the resulting sum is 100%.

A Mad Dog, Muncie, Indiana.

Viewed from the point of view of American females, 100% of "Mad Dogs" are undesirable vestiges of your bachelor life, when your ability to select your friends was not constricted by outmoded and hide-bound rules imposed by females.  Rules such as "Should have nice wife/girlfriend," "Must not burp" and "What kind of lunatic has a komodo dragon for a pet?"

Mad Dog, with dog.

Your Mad Dog probably stuck by you when you really needed a friend, like the time that girl who was studying Hindu culture dumped you because you ordered a hamburger when she took you to an Indian restaurant.  Or perhaps Mad Dog was there for you as you were about to cross some major threshold into adult life, pulling as hard as he could to stop you.  Consequently, you can't drop Mad Dog like a hot rock just because your significant other finds him to be somewhat deficient in the civilized graces she expects you to possess, like not showing your kids how, if they stay in shape, they'll be fast enough to escape injury when they throw a can of spray paint onto the Weber grill.

Mad Dog, calling you for last call.

What wives and S.O.'s need to know is that Mad Dogs are essential to our way of life, just like the rain forest.  The rain forest is full of poisonous snakes so you wouldn't want to live there, but without it we'd run out of oxygen--or something.  Mad Dogs may not be ideal guests for a backyard croquet party, but they are the ones who drink tequila until last call with girls named "Sheena," then go off and get matching tattoos.  If they didn't do it, we might have to.

Think of your Mad Dog as sort of a human rain forest.

So your job, as a friend of a Mad Dog, is to find ways for him and your S.O. to co-exist peaceably.  Here are a few tips from the last four decades of my friendship with my Mad Dog, and my two decades of marriage.

Don't invite Mad Dog to your wedding.  Big mistake.  Your wedding day is the time for your bride to be the center of the universe.  You do not need a rogue asteroid like Mad Dog careening through her solar system, crashing into the heavenly bodies--her bridesmaids--that surround her like moons, dragging them onto the dance floor and asking Sy Oliver and His Society Syncopators if they know anything by Bob Seger.

Society orchestra: Caution, do not mix with Bob Seger.

If Mad Dog asks whether he can crash at your place, the answer is no.  The downside is too great on this one.  Mad Dogs sleep late and tend not to shower before entering the kitchen and asking "What's for breakfast?"  Mad Dogs also don't do dishes until they are stacked in the sink like some misbegotten work of modern architecture.  Mad Dogs also don't bring cute "hostess gifts" or send "bread and butter" notes thanking your wife for having them. 

They're not going to wash themselves.

If your wife asks if you know any nice men who might like an unmarried friend of hers, do not suggest a Mad Dog.  If your wife's friends wanted to meet a Mad Dog, they could have done so by dropping into any one of America's many clean and friendly biker bars, or attending a National Hockey League game.  In fact, Mad Dogs tend to find their future spouses by looking for women who can whistle through their teeth at professional sports events.  It's sort of a mating call.

A future Mrs. Mad Doggette

If, by following the foregoing rules, you find that you are gradually losing touch with your Mad Dog, this is the price you pay for a happy and stable home in which to raise your children to be thoughtful, well-mannered and productive citizens who receive Certificates of Commendation at their high school Senior Awards Assembly.

Unlike Mad Dogs.