100% Cotton - (T Shirt)
Piece of thick cardboard - for placing inside T Shirt
Sharpies - preferably with thick 'nibs'
95% Alcohol - (make sure your room is well ventilated)
Draw dots with Sharpies on to your T Shirt
Gently drop alcohol on to your dots - they will spread.
Let them dry.
Place in tumble dryer for about 15-20 mins, then wash.
Pure silk can also be used.