You start one song, then as soon as you see the text message ("your
wounds begin to heal") you stop singing and start the second.

FYI since reading about the hotkeys here one the list i can now TWIST
(my vote) 3 songs successfully 95% of the time, only bashes and stunns
throw me off. Makes my soloing 100% easier! can kill most blue mobs
(dervs at the present) with 75% HP left.

<snipped message below>

Ok, this may sound silly, but I've actually had people ask this, and
wonder
about the "REAL" definition of juggling/twisting/mixing/stacking....

When you juggle, you start the first song. Ok easy, so far.
WHEN do you start the second?
Do you start the second immediately when the icon for that song comes
up? Do
you start it immediately when you see the expected text in the textbox?
(If
it sounds stupid, I've actually seen so many times where the icon does
NOT
go up at the same time as the words appear in the text box). Or do you
click
a song, don't wait for anything and click the next song right away? Do
you
start the first song, and wait to start the second until the graphics
for
the first song take effect? (i.e. the little blue sprinkles for Hymn,
etc.)