I suppose you could imagine rolling out of your body to begin a lucid dream after WILDing, but that's not the way I do it. I perform the action of getting out of my bed as I would if I was awake, but since I'm under SP and am actually dreaming at that point, I'm really getting out of my "dream bed" to begin the lucid dream. I just find it more effective than imagining because its like you're actually doing an action.