For teak I use a red mahogany stain, oil based, diluted 50% with Japan dryer. I add a small amount of tung oil. Mahogany is tuffer to get the match. And it needs to be filled. I use filtered sanding dust, either teak or mahogany, for a better color match, mixed with TiteBond Hide Glue. Regular glue wont stain, hide glue will. I put a little red stain in the filler. Let it dry then lite sand. Mix the stain/japan dryer progressivly redder (more stain) until you get the color needed.