^ Exactly. And you do have to play with it a bit and see what your horse responds to the best. Some horses respond to you taking the contact, and others need to seek it our on their own, that's what I've discovered at least. Also, a lot of the time my horse will give once I release, rather then when I take.
But I do not recommend "see-sawing" or really even too much "sponging" of the reins. Note, I said too much, not never. Every once in a while taking a feel of each rein for a moment can refocus my horse when he's getting distracted and strung out. However, it's MUCH more about your legs, your seat, and your upper body then your reins. Hands come last.
I give myself very good advice, But I very seldom follow it