In a double boiler, melt your chocolate and add a splash (1/2 tsp or so) of vegetable oil to help the chocolate not to seize up. Once completely melted, pour half into one bowl and half into another.
Add food coloring to one bowl and then the other color to the other bowl. Give a good stir so the dye is throughout. Dip your marshmallow in the orange first about 1/3 of the way up and then set on some parchment paper.
Proceed throughout the marshmallows doing the orange. Then repeat, only lower, with the yellow. Set on parchment. Then do the eyes with the gel tube. Avoid putting too much of a dot for the eyes or they will drip.