Also, technically the give should be towards the horses mouth, not up in the air so the reins don't actually change length
You will probably find it better to take reins back smoothly using a downards D motion, not in a straight line. Imagine a D facing the ground. You give alond the straight bit, and take along the curve. The idea is that the horse maintain its own outline during the give, and you retake smoothly so nothing happens to the horses outline (or rhythm) at all.
Good Luck and have fun.