Food

Picar [] to have a snack
Example: ¿Hay algo para picar? Is there anything to snack on?

Papear [] To nosh/to eat
Example: El papeo is to "grub". Ya es hora de papear algo [] It's about time we got some grub.

Ir de tapeo [] To go for tapas.
Example: ¿Te apetece ir esta noche de tapeo? Do you feel like going out for tapas tonight?

Drink

Una birra [] Slang for beer

Estar pedo, peo [] To be drunk.

Tener un pedo, peo [] Lit. To have a buzz. To be in a state of drunkenness. Not to be confused with tirarse un pedo, peo [] to fart.
Example: Manolo tiene un pedo de mucho cuidado [] Manolo's really drunk.

Empinar el codo [] Lit. To lift up one's elbow. To have quite a few drinks, referring to your arm's position when drinking.
Example: A estas horas ya estará en el bar empinando el codo [] At this time he'll already be at the bar having a few drinks.

Beber como una esponja [] Lit. To drink like a sponge. To drink a lot.

Estar mamado/a [] Lit. To be breast-fed. Another way to refer to being drunk. Also when something is very easy.
Example: El examen estaba mamado. The exam was very easy.

Echar la pota/la pastilla/la papilla [] Lit. To throw out the pan/the tablet/the baby's puree. To be sick / to throw up.
Example: Ya echó la pota dos veces [] He's already been sick / thrown up twice.

Una resaca []A hangover.
Example: ¡Joder! ¡Menuda resaca tengo! Fue el puto vino de ayer [] Fuck! I've got such a hangover! It was that fucking wine I had yesterday.