breathing vs relaxation problem

Breathing correctly has enormous health benefit as well. Belly(diaphragm) breathing should be your every day breathing method as well.

When I started doing Aikido, I forced myself to change to belly breathing. It wasn't easy and took me a few years. But I did it. Now I breath naturally with my belly even in my sleep.

You may want to practice belly breathing without Aneros.

Hey Grayfox,
I think the greatest issue we Anerosians have with breathing is that Zazen is taught and practiced with the body upright and in a symmetrical posture (see refs at bottom of post.) We are forced to translate our breathing practices and focus into a horizontal/prone posture where the gravity vector doesn't work symmetrically on our lungs, muscles, facia and tactile/sensory systems. So we have to filter out a lot of contradictory feelings as we breath. Our distractions are many including wrinkles in the bedding. Far from the least distraction we have to deal with is the sensual fire being stirred up by the hunk of plastic we just stuck up our ass. None of this is covered in any of the Zazen teachings. So I improvise.
I practice breathing meditation as a sort of two step process. Once inserted and settled into a body position and posture that supports good tool-prostate contact I start my breathing routine.

My goal is eliminate any perceived goal by a horizontal bastardized form of Zazen (upright) breathing:

a. Establish a generous level of oxygen in the bloodstream to avoid hyperventilation or a need to correct for too little oxygen intake. This is aimed at supporting, within two or three minutes, a steady pace of breathing that's relaxed, not artificial, feels natural and requires no mental monitoring or attention to 'control.'

As Hyrdogen points out, the 'diaphragm/belly' mode of breathing should be automatic and require no thought. Practice your belly breathing somewhere else in your daily life, not when you are entering an orgasmic session.

Once I'm comfortable with this breathing routine I focus on a most minute element of breathing. Some teachers say 'listen to your nostrils.' I've chosen the feeling of the airstream in the back of my nasal cavity where the flow is bent downward into my pharnyx. (find your own focal point that really stands out.) I try to focus on a spot smaller than a dime. This is basic Zazen -- easy to do when sitting in a chair, more difficult to translate into a resting posture in bed.

The tough part of this practice is occasionally doing a mental check on how breathing is going without triggering a thought pattern that adds 'brain noise' to the equation. (allowing brain noise will give rise to wondering how much detergent is left in the carton in the Laundry room). Our human intuition and inborn desire to 'creatively think' works to destroy every step along the path to orgasm. My meditation guru allowed students to check the clock occasinally. I think though that the 'status check' should not reach outside my 'meditation coccon.' I keep my eyes closed yet am intense about feeling those air molecules travel past my point of focus. There is nothing else worth considering, just the airflow.

b. With focus just on that bending of the airflow, I want the Aneros to fade into my being and the p-tab and body of the tool to "wed" with my Prostate and rectum. It usually takes me from 20 to 30 minutes to reach this state. The guys who are really 'rewired' do this at lightspeed. Being an anal junkie it takes me much longer. "Realizing" that the Aneros has 'vanished" is the signal that 'I've arrived.' I want to cherish and enrich this state of being so will stay with my breathing for several more minutes sort of 'testing' the degree of relaxation I've attained. If I feel myself relaxing more I know I wasn't 'really relaxed.' So, it's time to focus on airflow once more. To do otherwise would produce a 'dud session.'

If this all sounds contracdictory, you're right! I've sunk through stages of increased focus on that dime-sized portion of my head. I've supressed most of my sensory system and minimized brain noise without going to sleep. I am no longer aware of sensory crap like a winkle in a sheet, a damp spot on my towel, a toenail that should have been trimmed or an itchy point on my ear lobe -- All of that 'noise' is gone. Yet somewhere I'm managed in my 'nothingness.'

c. Now my Zazen meditation phase is drawing toward an end. I'll selectively turn on my senses (rumel, in his AAA discussion refers to this as opening a filter) As I move from deep meditation into my most subtle 'sensing' mode I 'listen' for my Prostate and Aneros to be moving in response to my breathing or my heartbeat. My focus at this point is on sensing just which two sensory nerve endings on my prostate are being alternatively stimulated by the aneros. I supress the desire to contract and physically move the Aneros. I focus to hold off the rise of orgasmic energy and the pleasure I crave. I try to ignore the other intense noise taking place in my pelvic region. I open the sensory filter a bit wider and find out what other faint sensations there might be. If it's an anal tickle from the Aneros I push back against any sudden surge of that desire to contract any muscle. This moment is about my Prostate, not about my anus. I'm living in just this moment.

I slowly let go and permit my breathing to automatically synchronize to the rhythm of my prostate or perhaps a multiple of the heartbeat that emerges in my penis bulb. Now the focus has shifted away from airflow to another tiny sensory point somewhere in my body. Sometimes this is a 'wrong turn' and distracting. If so I'll push back a bit and re-establish my breathing pattern. What's my batting average -- around 0.250.
Hope this helps.

Zen Mountain Monastery: Zen Meditation Instructions
Questions to Master Deshimaru: Can you talk about breathing during zazen?
ZenSpace - Attention to Breathing in Meditation

One trick I use is to separate yourself from your mind. It's very easy with assistant of weed. Then you can let your mind wondering around and you become a passive observer to "read" your own mind. It sounds strange. But think about this: your hand isn't you. You can look at your hand in a passive way. It's the same with your mind. Your mind and you are two totally separate entity. Just like in your dream, you're a stranger in your own mind.

That's why it's easier to when listening to music. You let yourself lost in the sound.