At the moment I'm working on the articulation exercise too-too-too-too-tukutukutukutuku and just trying to push it a bit without tensing anything up. But I seem to be hitting a plateau. I can vocalise "tukutukutukutuku" at a decent lick, but the moment I put an embouchure on it, it slows up. Also tends to be more of a "tookutookutookutookutoo". Pretty much the same with the diggerdiggers and daggadaggas. Is it just a matter of 6 months persistence or is there a mysterious magic fix out there?