Let's look at a few bathroom customs around the world. The Bathroom Diaries was most helpful in adding to the intellectual part of my post. I mean, peeing is a serious thing. And if you want to be culturally appropriate, you'd better learn how to do it in context.
For example, when in China, you may find babies with open bottom pants and no diapers. Why? Because their mothers teach them to pee on command. They hold the baby over some kind of opening (street sewer, empty bucket . . .) and make a certain noise. The baby pees. If you are a baby looking to visit China, you now know how to pee in public there.
If you are an adult visiting China, I'd recommend you NOT wear open bottom pants and pee when people whistle. Find a public restroom. It may be a squatty potty, it may be a hole in the ground, but DON'T pee as a baby does. That's gross.
Not let's move to Turkey. There, you will also find a squatty potty. Even your hotel and apartment will have one. Since Turkey is an Islamic country, you won't find women peeing in public. You may however find men peeing in public. Americans do this too: when they are drunk, when they think no one is looking, or when they have to go really really bad and a bathroom is nowhere in sight. In this instant they say: "Well, I'm a guy and men all over the world pee in public, so I will too."
So what do Spaniards do? They use public bathrooms. But once again . . . you are more likely to find men peeing in public than you would in the states. However, Spain is still different. Imagine you are walking with your 3 year old. She says, "Mommy, Mommy I have to go NOW!" What do you do? In the states, you would tell your husband, "We have got to find a McDonalds NOW. I didn't bring a change of clothes and I don't want to carry a wet child around." Nope. Not here. It's much easier. When your child cries, "Mama, Mama . . ." You simply find a tree, or a sewer, pull the child's pants down and help them squat. Ya esta. Oh-and then you pull toilet paper from your purse to clean up the child because you expected your child will need to pee in public. I have to say this is one custom I won't be adapting. Unless it's an emergency. And I can't find a McDonalds.
I'd also like to take the time to do a little confessing. One summer when I was young (think lower elementary age), I was at a church softball game. Yes. A church softball game. I was playing with some friends behind the outfield. I had to go to the bathroom REALLY bad. The bathroom was WAY over by the pool. I didn't want to walk all the way over there and miss out on the fun. So, I noticed there was a nice row of trees between the outfield and the highway. Yes, I said highway. So what did I do? I decided to urinate (I can't say pee-it makes me sound even more gross) quickly behind the tree. None of my friends saw, and I hoped no one on the highway (which I somehow failed to notice was there) saw. All was good until I went back to the bleachers. You know how they say Mothers see everything that goes on in their children's lives? Well my mother has binoculars for eyes. Oh yeah, she saw everything. She saw me playing with friends, then contemplate whether I would walk to the bathroom or not. I'm sure her heart dropped as she watched me make the stupid decision to pee behind the tree. Obviously I wasn't that well hidden since she saw me . . .
So the lesson here is that no matter where you are in the world, you can pee in public. But you never know who is watching and what strange conclusions they might draw about you.