I tried doodling a mug. I used Sharpie markers. Then I heated it in the oven. I cooked it a couple times at 350. I would draw some and heat it. Then draw some more and heat it again. I had some smearing and I am not happy when I look at it close up but maybe it will inspire you to try it. The mug was on clearance somewhere for 2 for $1 so if I get rid of it and try again, it won't be a loss of much but my time.