Getting my feel around Blender and it isn't as difficult as it initially looks but this 'painting directly on the model' feature has totally confused me.

I know the prereqs for 3D painting are having UV unwrapped the model first (I use smart unwrap to make it sloppy but easy without concerning myself over seams just yet) in Edit Mode but after de-selecting my unwrapped object (with an open viewport for Front, UVMap, and Buttons) and then going to Texture Paint mode, my unwrapped map disappears, my object turns into one solid color with no shape other than its basic outline and although I have the brush cursor available, it will not allow me to actually use it.

What am I doing wrong?

BTW, I have gotten this to work before but how I did it then and what I'm doing wrong now is what is baffling me.