What can I use to paint fine details instead of a small paint brush?

I am using marzipan as part of a cake decoration and am wanting to paint on some small letters but I do not have a small paint brush- does anyone have any ideas what I might be able to use instead?What can I use to paint fine details instead of a small paint brush?
toothpick . the wood should hold enough of the ink or paint to use..What can I use to paint fine details instead of a small paint brush?
I would maybe try a toothpick or a wooden skewer.
Artists in olden days also used knives to paint
I've used toothpicks, sewing needles and recently I used a cat whisker. (I didn't pull it out--for some reason I can't bear to throw them away when I find them on the carpet.)

wedding make up