Nor am I particularly referring to the stoicism it takes to resist the provocations of queue-cutters, traffic-light jumpers, bus-lane hoggers, foghorn-hooters, headlight-flashers and other assorted highway rogues.
I am not even thinking specifically of the salty, not to say testicular, language that comes in handy when confronted with the hand-signals and jibes of certain road-users who make insinuations about the sexual fidelity of your loved ones or the social origins of your mother.
No, the balls I am thinking of have nothing to do with the usual cliches of motoring all'italiana.
In fact, they come into their own just when you might have thought that all the terrors associated with driving in Rome have subsided - once you have turned off the engine and got out of the car. Sadly, it is the fate of car-owners in Rome that they can never really stop worrying. If they are not being persecuted on the highway by bands of souped-up Fiat Unos, they are worrying about the legality of their parking spots, the chances of having their bodywork bashed or - worst of all - the prospect of having their darling vehicles broken into or stolen.
All of these are very real fears. Bumps and bashes are the inevitable consequence of driving in streets laid out in medieval times. Parking nightmares are unavoidable in a city that has almost as many cars as peopleand precious few garages.
Finding a secure parking spot is often more to do with your relationship with your local traffic warden than with the legality of where you have left your car.
In the centre, where parking is theoretically banned for all but registered residents, drivers lay out all manner of documents on the dashboard - residency papers, rental leases, telephone bills, birth certificates - in an attempt to prove they have a right to be there. (The town hall does issue parking permits, but they are usually out of date by the time they arrive.)
But crime is the real worry. Car thieves in Rome strike every 10 minutes on average. Even though 70 per cent of vehicles have anti-theft devices or alarms, that does not seem to deter them. Most alarms can be disabled within seconds by an expert; as for the various reinforced steering-wheel clamps you see on sale in Britain, they are useless in Italy, since a well-trained thief will simply saw through the steering-wheel (average time: about 20 seconds) and slide the clamp off.
So what is a poor car owner supposed to do? Two weeks ago your humble correspondent sped confidently into town in a newly bought second-hand Renault. Perhaps the British number plates made it an irresistible target, because within a few days one wing-mirror had mysteriously disappeared and a back window was smashed.
But at least the vandals did not abscond with the whole thing, as no doubt they intended. Why? Because our zippy little car has balls. Or rather, what in Italy is invariably referred to as "the anti-theft device with balls", made by a suitably macho-sounding company called Bullock. This is a sprung metal clamp which you fix round the foot-pedals and lock into place - acknowledged by the experts to be the most efficient deterrent on the market.
The "balls", as it turns out, are no more than two rounded rubber covers on the ends of metal rods that rest against the floor of the car as you press the device into place. Rather puny little things, if you ask me, and certainly not worth all the fuss made about them. They always say that Italian men like to exaggerate in the genital department, don't they? Well, I don't care. These are balls that are really worth having.