Here's an old video of me... at 1:34, I do some of those tick-tock things. Bad, bad.
And you know, if I remember right... I was having lower back issues when I was working on that piece which makes total sense to me now.
As for posture, I hate to post an example, particularly since this girl is so adorable, but it's important. Here she talks about protecting the lower back, but this is a very popular posture in belly dance that is detrimental to your body. (The tuck harms, not helps).
Most hip movement, within a comfortable range of motion does not harm the back at all. I'm not saying you can't bend the knees or tuck the pelvis... it's just not a posture you should apply as a standard or neutral in dance. Besides that, try tucking like this and bending the knees... hold it... now walk. Does it look pretty? ;-)
Anyhow, I think that's about all I should share... There's tons more, but this will give you an idea. For more info, you've got to take the course. ;-) Hadia does a much better job at describing these things than I do, anyway! And better still, she clearly illustrates and proves her findings.