It took me a long time to get the timing of charm right. Mainly because I
didn't use it at first because I didn't realize how powerful it was.

After MUCH experimentation, here's the best method I've found to get the
timing...

First you need to know the timing of your regular songs pat. I can do 3
songs with no trouble and about a half a tick of leeway if I do it right.
(if I anticipate the pulse and drop my songs earlier I can get 4, but it's
unreliable and very difficult in a fight)

I usually do this:

Charm
Off Song
Off Song

slight pause to allow for the leeway. (anywhere from 1/4 of a tick to 3/4 of
a tick depending on how good my juggling was and whether there were any
dropped notes)

Re Charm

Lack of room on my palette usually requires me to sing the same off song
twice, so I try to make it a useful song for the situation. (usually pixie
strike vs high caster concentration areas or snare if there's no druid.)

My palette is organized as such:

1) Charm
2) Off song
3) /pet attack (social key)
4) /assist [main tank] (social key)
5) /pet back off (social key)
6) /pet guard here (social key)

/pet back off is there in case my pet decides to beat on a party member
despite my orders and /pet guard here is there so I can stop him from pacing
after he's finished killing his former teamates and I'm waiting for charm to
break.

It takes a while to get used to the timing, but once you do, you may never
demem it again.

Draelon Stormsong
Bard of the Tribunal