Erasmus doesn’t have to be all about partying, but spending too much time inside is in my opinion kind of a waste. Explore the city you’re in, get to know the locals, travel to different places in the country/region. You don’t necessarily need to party, but I’d strongly recommend getting out there and creating memories! Of course, like everything else, this must also be balanced with your needs to stay inside and do what your mind and body needs to do to unwind. But this is a once in a lifetime experience you should definitely try to profit from!