To have interaction with Styrofoam or to see Styrofoam when you are dreaming, is interpreted as suggestion that you are undergoing some form of transition in your life. In particular to see a Styrofoam cup, when you are dreaming, can be interpreted as symbolism that you have a belief of insecurity. Maybe you do feeling insecure or unstable in a relationship.

…To see Styrofoam in your dream, indicates that you are undergoing some form of transition in your life. In particular to see a Styrofoam cup in your dream, suggests that you are feeling somewhat insecure or unstable in a relationship….