I do Pilates, mostly because I've had a bad back for years and it helps to stop everything locking up.
There is a great series called 10 minute Pilates it gives a series of workouts that are short, but you can stitch them together to make a longer one. Very highly recommended
My logic is it cant do any harm. Although not sure I'd fancy going to an actual class and think I'd look a bit of a plank!
I'd have a go at this video, but probably not in the same way you did. Hellloooo Adriene!
About two thirds of the way through she explains about people pushing their bums out too much. In fairness if be happy watching her stick it out too much a bit more often!