This mod is very small and simple, you can right click a block (any block) with Magma Cream and it will "cream" that block. This will cause the game to not be able to lay snow on that block.
To "un-cream" a block, you simply right-click it with an axe and it will remove the cream.
This does not come with any visual difference, however when you are near the block and holding magma cream in your hand, it will render a magma cream above that block in the world.
This mod also comes with some commands that let you interact with the creamed blocks (Permission Level 2 required).
These are: