The dictionary will tell you that word puto means male prostitute. And it does, but it can also mean a lot more.
Puto is also used to call someone gay. And of course puto doesn't actually mean gay, it's more like faggot.
No puedo creerlo, mi primo es puto, pero lo amo
I can't believe it, my cousin is a faggot, but I love him
Ese wey es puto
That guy is a faggot
No sabes lo puto que te ves
You don't know what a faggot you look like
Puto can also be a way of calling someone a coward, or more precisely, a pussy.
Echate una chela, no seas puto
Drink a beer, don't be a pussy
¡Andale! ¡No seas puto!
Come on! Don't be a pussy.
¡Vamos, golpealo, no seas puto¡
Come on, hit him, don't be a pussy
Puto can also function as what I like to call a sentence enhancer.
¡Oye, mueve tu puto culo gordo!
Hey, move your fat ass!
¿Quién se llevó mi puto celular?
Who took my fucking phone?
Puto carro no arranca
The fucking car won't start
No me hizo ni puto caso
She didn't pay me any fucking attention
¡Que puto calor!
It's fucking hot!
No tengo ni puta idea
I have no fucking idea
Notice in this case it changed from puto to puta. That's because the word idea is feminine, so we have to make the switch. While we're on that note, I've even seen the word puta used on it's own.
Puto can also be an insult.
Pinche puto, te voy a matar
Fucking faggot, I'm going to kill you
And when you insult someone like this, they don't actually have to be gay.
Oddly enough, you can also use it with your buddies.
¿Que onda puto?
Although puto is a bad word, in this case it really has more of the feeling of dude. Just make sure you really are close friends before you start tossing this around.
There's one last thing I need to tell you. Like all curse words, they can mean different things to different people. What puto means in Mexico may not be the same in Spain. Know your audience. What I've written here should be accurate for Mexico and probably most of the Spanish speaking world, but consider yourself warned!
And there you have it. Use what you learned today at your own risk, but the word puto will definitely add some color and fun to your Spanish.