I think you have to control the materials to an extent, but it's important to let the materials have a kind of power for themselves; like the natural power of gravity, if you are painting on a wall, it makes the paint trickle and it drips; there is no reason to fight that.
Keith Haring Doodle Stickers for Water Bottles 50 Pack Cute,Waterproof,Aesthetic,Trendy Stickers for Teens,Girls Perfect for Waterbottle,Laptop,Phone,Travel Extra Durable Vinyl (Keith Haring)