This is a method for creating an immense amount of energy in your body. The energy is basically kundalini power, but it is very sexual in this case (I have been able to project it as a 'calming' kind of energy, in the way that an embrace between lovers is calming, but in the end, it's pretty strongly sexual

If you ever manage to observe an entire lion's body as it roars, you can observe its belly moving outwards even as the air is leaving the lungs as a mighty roar. The movement is particularly in the lower belly.and this is an important key.
In order to breathe this way it is easiest to start with the chin upon the chest (back straight if you're sitting, or you can get down on all fours with back straight as per the yogic lion pose). Now make an, "aaahhh" sound (preferably as sexually as possible) and begin tilting your head back smoothly. As you tilt your head back draw the sound out "aaaaauuuuuuuggh" (I tend to do it like a cat in ecstacy, "aaaaaaaaauuuuuwwwwrrrrlllllll" but perhaps that's only my own tastes coming through, I swear it makes me feel sexier though). If you're sitting up you should end staring almost at the ceiling, if you're on all fours you should end looking ahead of you (or if you're on your back you should end with your spine nicely arched and your head thrown back

The startling thing about this breathing method is just how much energy it creates. For one thing, it can cause extremely intense orgasms. Additionally, I am male and I can have multiple and continuous extended orgasms from it (depending on how turned on I am going into it this can take awhile to build up towards). The point I'm trying to make here is, you can create MONSTROUS amounts of energy with this method. Sometimes I will use it to focus and relax and get an energy boost for a particular task, either spiritual, mental, or physical. It's got all kinds of uses. If you're into invocation of entities it can be helpful for that also.
If you read Liber 66 "The Stellae Rubae" (not "The Star Ruby" in The Book of Lies) by Aleister Crowley, I believe he is referencing something similar in the last line. He describes the Lion as the male sexual atavism (see his tarot card deck, for instance), but I have tought two women this method as well and they enjoyed the ever loving hell out of it. At any rate, I think there is a precedent for this in western occultism, in case anyone cares

Oh yea, and this entire meditation gives you a hell of an abodominal workout.
Jonathan (McCavity Cat)
PS: My experience is that some folks could care less about this, and some people think it will be a benefit to them spiritually or sexually or whatever. I would be happy to help anyone 'get' this as well as I can. Just email me privately and I'll try to answer any questions you have.