Explain Aperitivo to a 5-year old

You find a place to have a drink. Any bar, any cafe, any hotel bar. You order. The drinks will be brought out. You enjoy. Some nibbles will be brought out with the drinks. What is offered depends on where you are. The fancier the food, the more expensive the drink. They're not bringing out a meal. It's just supposed to be little snacks to enjoy with the drink. It could just be chips or some olives, etc.

I don't understand why you would be considered a moocher. You can't keep asking for more food without ordering another drink.

It's nothing more than having an afternoon drink before dinner.

In Milan, you will find many buffets laid out for aperitivo, so you won't have to ask anyone for food. Drinks will be a bit more expensive during aperitivo hours but will include access to such buffet.

This is what we’ve found out too. Only in Milan could you make a light meal of a drink and appetizers set out in a bar during aperitivo time, early evening. In Venice, our granddaughters were surprised when they delivered 5 little bowls of salty nibbles with our bottle of wine and their 2 non alcoholic 22€ drinks. They asked if the nibbles were free. I told them that in that instance they were “free” and we were paying for the view and memory, enjoy.

I'm not certain, but I believe apericena (lots of food along with the drinks) may be a thing in Turin as well as Milan. And something was said during a 2015 Bologna walking tour about folks who didn't want to cook for themselves making a meal of cocktail nibbles, so perhaps the concept is spreading.

Regarding apericena: yes indeed, some of those buffets can be quite substantial / filling, with enough focaccia, cold cuts, cheese... to make for a light dinner. At least in Milan. I vaguely remember seeing them in Turin too, but Turin in drizzly November (when I visited) deserved more hearty fare 😂.

A tip, at least for Rome: just order your drinks, do not ask for food, and they will bring the snacks. If you request food, they bring a spread that's slightly more elaborate, and you will be charged. Also some of the more touristy spots, such as the places on Campo dei Fiori, have minimal snacks (small bowl of potato chips, peanuts). My personal favorite for aperitivo with good quality food is Negresco, located on a side street off Via del Corso in the shopping district. They also have a good drink menu, beyond the usual spritz and wine choices.
Buon apetito!

Are the mannerisms the same in every city? Rome? Florence? Venice? Naples? Milan?

Nothing is the same in every city in Italy and - as you can see reading the above messages - the mannerisms change from bar to bar.

In Milan I followed a simple rule: "I'll empty the all buffet table unless they stop me. And I'll do it with a clear conscience: I am going to average 3 women on diet who pay for an aperitivo and eat one single olive".

In Venice and in general all across the Veneto, the aperitivo (which consists in a Aperol, Campari or Select spritz and some chips) is deeply rooted in the venetian culture and even if many people like to gather in early evening, generally after work, there is no specific time to have an aperitivo, you can go in a bar and have your spritz in the morning before lunch (in general from 10.00 a.m. to 12.00 p.m.) or in the afternoon before dinner (typically from 4.00 pm to 8.00 pm) alone or with other people.
In other part of Italy, especially in Milan, the aperitivo is a more "formal" ritual: it takes place typically in early evening (17.00 - 19.30) and it can include a buffet (like in the apericena) and other cocktails as well as spritz, it's rare to see locals having aperitivo out of that range of time. I remember the first time I went to Milan (I'm from Venice), it was 11.00 am and I popped into a bar to order an Aperol spritz.
The woman at the counter gave me a funny look and said: "a Spritz? You know what time is it?" . Yes, different places have different tradition when it comes to aperitivo, but there is no reasons to be worried , just watch what locals do, the basic guidelines are:
-in late afternoon, choose a bar or a cafe possibly with a nice view on a piazza,
-order a spritz or any soft drink if you don't want to drink alcohol, nobody cares. Snacks like chips or salty peanuts come with spritz in most of the cases (and they are free) , but you can order a tramezzino (or a cicchetto in Venice) if you want
-enjoy your time watching the world go by

It's not that dissimilar from going to a restaurant/bar for happy hour with your colleagues on a Friday after work. Just not as expensive.
I use the same method as Dario, except I'm big so, at the buffet counter, I try to average the amount eaten by 5 women on a diet who are paying for my food too while the rest/bar still makes a profit.

I think you can compare it to Tapas/Pintxos culture. It started out as buy a drink, get a simple snack. Snacks rose in complexity, then to buy a drink, buy snacks for little or nothing, then buy a drink, order a Racione, or the equivalent of an appetizer.

Basically, unless a place overtly advertises a drink with a snack, or one of the places that offers a buffet with a drink, don't be disappointed if you get only a drink. Some regions and cities, the aperitivo culture is more prevalent in Italy, other places not at all.

I would not expect enough to make a meal in any case.

Rick in his Venice videos pops into bars and eats

Thank you All. A rich array of viewpoints and experiences, just like the food and drink at aperitivo. I like Dario's method, one-upped by Roberto. Cin Cin!

We will be in Milan in Sept. We would love to go to a bar with this apertivo + appetizer bar. Any suggestions as to good ones?

Any suggestions as to good ones?

In downtown Milan finding a bar not making the Aperitivo is almost impossible. I pity the old drunks who just want a coffee between 6 PM and 9 PM without eating, laughing and being surrounded by hipsters, models and nice people.

Last time I went to Clotilde Brera, 6 San Marco Square. Not surprisingly it's in the Brera neighbourhood, not far from Lanza Metro stop. Google it, I don't know if it survived Covid.

I recently stayed in 11 cities in Italy in the Lombardia, Veneto, Emilia Romagna, Umbria and Lazio regions. My husband & I haven’t had the apertifs on past trips; we usually just waited an hour or two for the later dinner hour to eat. But, since I was staying in a lot of less-touristy locations, no one was eating dinner before 8pm or later, and I was starving!

So, I sat down at the Cremona Duomo Piazza, and after greeting the server, told her I had no idea what to order. She brought me an Aperol Spritz along with a slate “plate” with olives, chips, peanuts and a few delicious sandwich bites. In that city & location it was 5 Euro. (Mantova, Bergamo & Perugia were about 5-7). Well, everything was delicious, and I wasn’t hungry enough to eat for dinner afterwards.

I had a few more in other cities with the most expensive one being at the San Marco Piazza in Venice where I purposely decided ahead of time to sit at one of the outdoor tables at the Florian, listen to the lovely music and let time stand still as I enjoyed my last evening in Venice.

Per your question about being a moocher, at all of the restaurant locations I observed across the regions or the few where I had an aperitif, all of them brought the plate of predetermined food to the table. There wasn’t a buffet. But all of my observations were at outdoor typical piazzas, not fancy hotels.

I do remember my husband & my first evening in Padova years ago when we couldn’t figure out where we could have dinner at 6pm. We saw a lot of people eating outdoors, but it was all apertifs & accompanying salty snack food! Didn’t anyone eat dinner? Then magically, an hour later, out came the white linen tablecloths and the places were serving dinner.