I agree with John's statement about "нажраться" being somewhat equal to "to get wasted". Just to be clear though, using just "нажраться" without any further detail would mean (for most of us at least) "get wasted with alcohol" (emphasis on 'alcohol' here), so if your "to party or something" does not imply that - choose some other word for it. I mentioned "any further detail" because the word "нажраться" in itself does not involve alcohol - it means "to eat A LOOOT of something" (it is a bit vulgar however, so the word "наесться"/"объесться" would be more appropriate ... although for peer-to-peer friendly conversation that would be OK ... and maybe even better) (and yes: "eat", not "drink"). So, in a conversation between friends the word "нажраться" is appropriate. How to decide should you use this word or not with a particular friend? - The same way you decide how to call a person: "ты" or "вы". If it's definetly "ты" - then you can use "нажраться" all you want (just as pretty much any other sleng words, vulgar or not). Also, "нажраться" is maybe vulgar, but then only time it can be somewhat offensive is when you are talking about somebody, and use like "he's got wasted" instead of "got drunk". And (finally) back to your initial question. You can just write to your friends: "Нажрёмся?" (Let's get wasted?) if you plan on doing some seeerious drinking or "Бухнём?" (slang for "let's have a drink?") if you just want to have some drinks (of course this arrangement of your's can become a scipt for the next Hangover movie, it's just that this version usually does not imply that right from the start)).

Нажраться just means "to get wasted", so I guess it depends on who you're talking to. I wouldn't say it to someone I'm not good friends with, since it is a bit vulgar (but not horribly so). You could also just say "Давай встретимся, что-то выпьем"- Let's meet up for a drink.

here it means to drink a lot

It's a vulgar and NOT a bit. It used among young males. Adults usually "outgrow" this sort of slang words unless they are low-class working men drinking on a daily basis. Women mainly use it for describing heavily drunken men (e.g. он вчера так нажрался, что еле приполз домой). I would definitely not recommend to use it as an invitation to drink something, especially if you're going to do it with your father or any girl may take part in your party. You may say something like Давай (давайте) встретимся и выпьем что-нибудь. As you'll be in Russia during the World Cup, the football will be used a lot as a pretext for drinkingt: e.g. Давай встретимся и отметим матч // победу нашей команды // отличную игру // проигрыш etc. There is another way to ask for a friendly meeting: Давай (давайте) встретимся и посидим где-нибудь... Here "посидеть" means "to eat and drink in a relax manner while talking". How much you will eventually drink depends on situation. For example, if a girl ask her female friend "давай встретимся и посидим", it means "let's meet up to drink coffee and chat". If a guy say it, it usually imply that they will drink alcohol.