If you are like me, drown proofing is the ONLY way-- in FRESH water (there may be some who can't float even in SW I guess). Simple-take a breath (big if you like) and let your body do what it wants. Your head/face will go under but the air in your lungs will make you float effortlessly, with the upper part of your back at the surface (assume it's the same for everyone?). When you need to, just kick a bit and raise your head for another breath. For the DM test you have to float 15 mins., the last 2 minutes with your hands out of the water. The chances of me doing that...........I practised and practised--every sort of arm/leg movement with no success until hearing about drown proofing on SCUBABOARD. Then it was a piece of cake, though you tend to spin a bit in the water. Perfectly legal (at least with PADI) for the test. Some think drown proofing means you touch the bottom at some point, which is "illegal"--not true. Instructors should make a point of mentioning drown proofing. I ramble on, but get frustrated when people think there is another way for us guys to float when there is not. And it's more practical than treading water no matter what your treading method, because for all practical purposes you can do it forever without any effort to speak of--and that's the point in case you do fall off a boat, no? Of course if you do fall off a boat, what's the boat doing while you float for 10 minutes?--unless you (and buddy?) dived with the boat unattended--but that's another thread.