Add red food coloring into the mixture, using only 3 tsp at first. Then add a couple drops of green food coloring to take the 'pink' edge off the red coloring. If the mixture is too light, add one or two teapoons more red food coloring. Add one drop of Peppermint extract if you wish a fresh minty blood mixture. I wouldn't suggest using the mixture on or in your mouth.
Real blood is foggy or opaque, but clear liquid looks better in a wine glass.
Add green food coloring one drop at a time, mixing thoroughly after each, until the 'pink' edge has been taken off the mixture. Pour into a wine glass, and swirl. The concotion looks very good under bright light, and moves with the viscosity of thick blood. If you plan to drink it, though, I recommend you cut it half-half with water. I was promised the recipe years ago, but only came across it quite recently.