I’m Italian and I live in Italy. If you come to Rome you may be lucky in that two clubs are located here that are the most famous in Italy: Olimpo and Flirt. Flirt is attended by very beautiful and young couples, some of them coming from other European countries so you can speak english if you don’t speak Italian.
Around Rome there are a couple naturist beaches with sexual activity after sunset or in spring/autumn.
Encounters here are organized via websites and social media, one to one. Often you can find someone who organizes parties in their home, as this is preferred over the encounters in clubs.
Strangers are usually very welcome, though you could experience difficulties in finding people speaking fluently enough.
If you have any specific question, just ask.