Stain with a rag/cloth/sponge, but the burst itself is best done with a spray can or gun. It is very difficult to get a really black stain on wood, it always looks a bit grey, and getting a nice graduated blend for a burst with stain is very hard to do. A bit easier using spirit rather than water-based stains as they don't seem to leave the 'tide mark' that water based stains often do, but still not at all easy.