Can we discuss this? I don't believe that Marx's definition of communism is a form of society that comes after socialism. I think communism exists now within the working class. Its the real struggle against capitalist class owned private property and capitalist directed production and distribution of the historic means of production.
I actually really don't like the definition of communism as something strictly "out there". Communism exists just as sure as capitalism exists. Socialism can become communist, but communism goes away when capitalism goes away. Communism is the negation of "bourgeois" private property. The left is already too idealist and prefigurative, and Marx was really against that.
If you ask me, the idea of socialism as the achievement of minimum demands, that leads to communism as the realization of maximum demands, is not a Marxist communist theory of change, it is a social democratic one.