Had a good rest at home today, cleaned my trombone's bell section and now the valves are quick again. I just don't know why they get sluggish. When I first started using light piston oil, it was fine. During the past week, it started slowing down. I hope it's just residue and not something I don't know about my valves.

I did some mouthpiece practice today and well, still not much progress. I've still yet to find that efficient and reliable embouchure for each note. Well at least there'll be time to think about it and practice soon.

Alright then, this concludes my day. Merry Christmas to you!