I long line D. I put the lines thru her stirrups but I have a spare leather which I tie under her belly to secure the stirrups to her sides. I'm another who never uses a whip, I have no need to. My horse moves amazingly well off my voice, she even turns to vocal commands. I long line around trec obstacles, over poles, lunging with two lines etc.
I think the main thing for me is ensuring the horse is responsive to the voice, I'd always have someone at the head to begin with and a second person in case you get in a muddle.