Peforlife-
You lie down on something (I use a weight bench) and have your feet propped up on a higher surface (my bed). The weight hangs down between your ass cheeks, your shaft is parting your balls on either sides. This is the position you should hang in. If you hang 8 sets/day and increase the weight each week (small increments - half pound or so at this point) you will gain. I gained a 0.25" of permanent erect length from about 1.5 months of hanging BTC 6-8 sets/day.
In total, I hung 4 months, but the first 1.5 months was skin stretch and getting used to the weight. Then another month was cementing. I had to stop because it hurts my back (due to improper form - I was slouched over in a computer chair for that 4 months. Now I use a weight bench, a flat surface).
I plan to start up again once my back is completely healed. But I guarantee you if you warm up with a heating pad, keep the heating pad on your pelvis while you hang your sets, increase the weight each week and attach properly, you will gain. Also heat up between sets.
The main reason I stopped is because I feel my dick is pretty much big enough. In other words, the back pain I get from hanging isn't worth the gains, since I'm pretty good already. But for awhile I was really intent on gaining, regardless of back problems, and I did gain.
Now I'm using PGE1 injections for gains. I am not able to give any advice/results at this point.
Good for you for being able to hit up 8 sets/day. That used to take me all night after work, like 5 hours after the warm down etc. Oh, and make sure you are hanging 20 minute sets. No more, no less.