If you do, what benefits have you derived from it?
I find it trains more of the discrimination factor for when you have too much sloth, it's a better exercise to take up. I find doing it in bed at night keeps me awake, whereas anapanasati will put me in a dream state.
Most sources seem to be vissuddhimagga based, I haven't really researched what the patisambhidamagga and other commentaries say about the practice, only that the Sarvastivadans used it first to weaken sensual desire before doing anapanasati.
https://suttacentral.net/arv11/en/anandajoti12.1 The Abandoning of Sensual Desire
Herein, monastics, what is the cultivation of meditation which, when practised, developed, made much of, leads to the abandoning of sensual desire?
Here, monastics, a monastic who has gone to the wilderness, or to the root of a tree, or to an empty place, in regard to this very body – from the sole of the feet upwards, from the hair of the head down, bounded by the skin, as it is placed, as it is disposed, full of manifold impurities, reflects with right wisdom as it really is:
There are in this body:
Hairs of the head, body hairs, nails, teeth, filth, skin,
flesh, bones, sinews, nerves, kidneys,
heart, spleen, pleura, intestines, mesentery,
upper stomach, food, stomach, liver, excrement,
tears, sweat, spit, mucus, grease, synovial fluid,
marrow, fat, bile, phlegm, suppuration,
blood, skull, brain,
(thus on this body) full of manifold impurities he reflects with right wisdom as it really is.
Just as though, monks, there were a granary with open doors at both ends, full of various and manifold kinds of corn varieties: grain, sesame, mustard, mung beans, meal and beans, and a man with good vision looking round would understand: these are bearded grains, these are fruit-grain, even so, monastics, a monastic in regard to this very body – as it is placed, as it is disposed, reflects thus.
This is the cultivation of meditation which, when practised, developed, made much of, leads to the abandoning of sensual desire.
This one is quite different from the suttas and vissuddhimagga which use.
Head hair, body hair, nails, teeth, skin
Flesh, sinews, bone, bone marrow, kidneys
Heart, liver, membranes, spleen, lungs
Bowels, mesentry/intestines, gorge, dung, (brain)
Bile, phelgm, pus, blood, sweat, fat
Tears, grease, spittle, snot, joint oil, urine