Don't let them intimidate you or force you onto a roundabout whe you have not checked your options. You need to check carefully that your entrance is clear, and also be sure where you wil exit. I find that Italian drivers are more sympathetic on rural roundabouts than in cities, although I'm sure there are exceptions.
Priority at roundabouts
The general rule is to give way to the left. Italy, like France, used to have an unusual priority system on roundabouts where you did not have priority once on the roundabout and had to give way to the right. In almost all cities in Italy they have removed this antiquated and dangerous system [indicated by a 'yield' triangle on each road entry point to the roundabout]. However, you still occasionally find them - I encountered one in Aosta in Northern Italy in 2004 but have not seen one since.
Lane discipline on roundabouts tends to vary from province to province. Don't assume that Italian drivers will take a logical route through a roundabout - it might seem logical to you. Keep an eye on both mirrors when exiting a roundabout, ensuring that you have no vehicle on your inside as you leave. You might observe that the majority of drivers do not indicate to leave the roundabout; I suspect the reason is that you can't trust indications!
Italian drivers tend to be quite impulsive when entering roundabouts, keeping braking to a minimum and attempting to enter without braking or stopping!