This is a variation on the standard I IV I arpeggio vocalises by adding V 6/5 at the end.
Begin slowly and then try to move through these arpeggios at a brisk speed. When I was first starting to move quickly in vocalises, I would often cover my ears to help moving through passaggi. I could hear a “clunk” noise when I was clumsy.
Of course, the accompaniment is to your taste. I just give a simple line.
Enjoy!
I IV 6/4 V6/5 Arpeggio Vocalise