When the three of cups appears in a reading, it is an indication of a time of celebration, partying, eating, drinking, and enjoying the company of friends.  It is a symbol that your hard work has paid off, and it is time to let your hair down and have some fun!

Three of cups is generally a very jovial, happy and exciting card.  Three cards build on the energy of the two cards, and is a natural progression from finding a partner, to expanding your circle of friendship and love to include others...

However, there is also a bit of caution that is needed.  Most likely the fun is innocent and positive in nature, but in some readings, it can indicate the presence of a third party that can interfere with your happy relationship,

If you look at the symbolism of the card, it is important to be aware of the vibe and the energy of the situation.  From personal experience, I would advise avoiding triangulating situations at all costs, as it can completely destroy the relationship you have built with your partner, and once that damage is done, it can never be undone.  

But in most cases, this card is a sign of happy times and celebration, just be aware!  

As with all journeys, there are ups and downs, and nothing can be taken at face value, use your intuition to discern the nature of the meaning for you.