Typically in class our warm up is 12-15 minutes (level pending) When I did an advanced workshop with Wendy Traskos we warmed up for about 20 minutes, When I do silks/trapeze that is about a 15 minuted warm up.
My warm up with Wendy started with sun salutations so I do this a lot in my classes, other times we just wiggle around the pole and begin slowly stretching our shoulders out then move to the floor and do a floor routine which includes mild stretches.
In silks/trap class I am told to begin in downward dog, the pigeon, then straddle – all stretches are held for quite a long time but are held very mildly until I am warm enough. I do not recommend this for new people as this method I’ve been told is based on yin yoga which opens up the tissue rather than elastic muscles. The other portion also involves climbing to the top of the silks and releasing yourself down slowly with legs in a V – so this is a rather extreme warm up.
You want to be limber before dancing but not so limber that you can tear a muscle which I have done from being overly stretched out. Stretching weakens your muscles so consider the integrity of a rubber band – if it’s too stretched out it will break.
If you have a stair stepper or treadmill, 5 minutes on that at an even pace will begin to get the blood flowing or you can use your pole and use transitions to warm up, after the blood is flowing stretch mildly and only hold stretches 10-30 seconds based on your comfort level. You really don’t want to feel pain or discomfort in these stretches.
In a cool down I teach and do myself deeper stretches, as Veena recommends.