I've seen in movies and videogames, probably cliché but they show Russians drinking vodka and partying to accordions during German invasions, probably as a way to calm the nerves. Did this actually take place normally?
As far as the drinking part of your question goes, this may be of interest for you.
I am not very competent in this question, but if you want a closer visual look at this, you may want to take a look at Soviet "The cranes are flying" (1957) movie that was shot only 12 years after the war so it was trying to be somewhat true to the reality. One of the negative characters, Mark, is shown partying and drinking in some scenes which is seen by other persons as disrespectful towards the hard war time.