the way I do them is with a little pre pop. I dont just pivot and lean, but instead pop, turn about 120 degrees, and then make contact with the snow, and press and butter it from there. i usually end up with a little stall out at 180, and then another 180 from there. I prefer to lean with my torso; you get a bigger press, and i think it looks better than when you just kinda pick your legs up.
Here's a picture of one of my butters from last year. (please disregard the skittles costume. that embarrasses me.)
so that's midway through, and then from there, I sort of nollie, which rights my body somehow, and then land forward after another 180.