If time is pressing or I have somewhere to be, I can distract myself from my erection’s passive insistence and get on with my life; but on those still dark winter mornings, when I wake earlier than I need to but am reluctant to leave the welcoming warmth of the duvet, I’m much more vulnerable. Then my erection snags at my attention, stretching itself slowly as it wakes from sleep, letting the foreskin slip back just far enough to release that salt-sweet-sweat smell with which it marks my territory.

Perhaps if I didn’t sleep naked, the erection would be easier to ignore, but it is the only thing between me and the duvet cover, which nestles against it like an old friend. Turning on to my belly only lets my erection show off the firmness of its resolve.

If this happens when I’m travelling alone, I give myself up to it at that point. I lie on my back, eyes closed, legs stretched, feet crossed at the ankles—I have no idea why—and let it off the leash.

Of course, by now I’ve had a lot of practice and I know exactly how to please myself. I have a particular hold I like to use, developed unconsciously over the years and now effectively involuntary. It is, as most things to do with my sex life are, complicated, slow acting and very, very effective. My thumb sits behind the head where it can roll the foreskin with ease. The index finger stays free, ready to stroke the sensitive skin of the head. The long second finger curls firmly below the glans, just at the point of lubrication. The third finger folds back against my palm so the back of it pushes the shaft out against the second finger and thumb. The smallest finger runs lightly, or sometimes firmly, over my balls.

Initially the erection swells just with the joy of being touched and knowing what comes next. Very little motion or stimulation is necessary. Then its short attention span asserts itself and it demands a mental porn show to prick it on to greater things.

These are never elaborate or even pretty. These are fantasies I would never admit to. The ones that I hope no one who knows me would ever attribute to me. In thrall to my erection, there is nothing I won’t imagine doing or having done to me, no boundaries, no decency, no love, just the need for one more twitch of the nerve endings, one (or more) holes to push into, women (mostly women, sometimes men, sometimes both) to use and abuse, until finally, back arching, legs stiff, hand moving rapidly and firmly, my erection sprays its hot sticky triumph over my belly, dribbling the remnants over my fist, like melting ice-cream, to pool in a sticky mess in the hairs on my balls.

During the actual release it is as if I am not there; there is just a blissfully blank moment of non-consciousness. Then, after a few seconds of pleasantly warm exhaustion, I am alone again and aware that I stink of sweat and semen, that the sheets are damp, that my hair is matted to my head and that I urgently want to be clean.

This, I think, is what sin feels like the opposite of grace, it drains the spirit and stains the soul. It occurs to me that poor old Onan, patron saint of masturbation, sinned not because "he spilt his seed upon the ground", but because he did it again and again and again, like an alcoholic soaking himself in booze although he knows he will wake in some gutter, covered in his own vomit.

Like most sinners, I indulge most when I am away from hearth and home, but even in my marriage bed, on mornings like this morning, in those vulnerably truthful moments between sleep and life, my erection sometimes snares me.

I test the extent of my temptation by rolling onto my side, pulling my erection up to the side and then releasing it. The thud it makes against the mattress tells me that it will not be ignored today. I turn and look at my wife, sleeping soundly beside me. I take in the reality of my love for her, the central place she has and will always have in my life, and I get out of bed.

My wife is not a morning person. She’d be accommodating I’m sure, but in a "Not for me thanks, but please help yourself" kind of way that I find bleakly discouraging and besides, when we have sex I want it to be about more than scratching an itch, so, needing to take care of things and not wanting to wake her, I head for the bathroom.

My erection wags as I walk, pleased with itself and pumped up by the idea that it’s leading me somewhere. I follow behind, with the same muted sense of embarrassment as a man walking a dog that insists on trying to hump every passing leg.

Showers are often advertised with pictures of soap-slick beauties achieving bliss under the spray. In reality, I think it is men, not women, who are most likely to masturbate in the shower. It’s private, you don’t have to explain why you’re taking so long and the mess is washed away immediately.

When I was young my erection would point upwards fiercely, as if trying to touch my, then much flatter, belly. Now it manages something just about at right angles and still feels proud of itself. Even when I don’t touch it, I can feel the pressure of its presence nudging me. Giving in to it, I brace my legs slightly apart, turn the shower to full force so that the warm water bounces off my chest and reach for the liquid soap that is so much a part of this ritual.

I pretend that my eyes are closed to keep the water out; the reality is that I want to concentrate on the phantoms I bring with me to the shower. Today my subconscious furnishes two women both redheads, the one in her twenties is slim and pale with taut breasts, hip bones like water-smoothed stone and that small tight gap between the tops of her closed thighs that makes my erection whimper with need. The second woman is a forty-something version of the first, with fuller breasts, a rounder belly and a large fuckable arse.

I picture them kneeling of course, each one pressing up against one of my legs, faces up-turned, eyes eager. They ignore each other as they compete to explore me but they cannot help, in this confined space, but rub up against each other. The enforced nature of this intimate contact adds to my arousal. In my mind’s-eye the younger one soaps my belly and works my balls with her long slim fingers, while the older one, perhaps more adventurous or perhaps merely more needy, parts my buttocks and pushes soap into that dark ripe crevice. In reality my hands are busy working up a foam front and back while my cock is screaming for attention that I enjoy delaying.

Swirling around me the two change places with an ease only fantasy could support. The older woman opens her mouth and swallows me until her jaw strains and her eyes bulge. She grips my buttocks firmly and forces me further down her throat all the time looking up at me so that I can see what this effort is costing her. The younger one has retained her hold on my balls and is pulling them backwards, using them to help her balance so she can push her tongue impossibly far up my arse.

Anyone looking into the shower now would see an older man, on the balls of his feet, one hand strangling his cock, the other pushing one long finger up his arse. My erection refuses to acknowledge this reality and drives me onwards.

I’m close now and need a final image to push me over. I imagine the older one with her back to me, hands above her head, stretching to reach the showerhead, legs spread improbably wide. My arms are wrapped around her chest and my fists are closed on the soft meat of her breasts, pressing her back against me. Beneath us, the younger one kneels, also with her back to me. Her arms reach up between the thighs of the older woman and then lock on with a trapeze artist’s grip as her hands grab the woman’s heavy buttocks and part them. Gleefully and brutally I feed my cock up the woman’s arse, relishing the grunts she struggles to suppress. The ballet is complete when the kneeling girl leans back; still clutching the legs of the woman I’m sodomising and stretches her long neck at an impossible angle to clamp her lips around my balls.

This Circe-de-Porn triptych is so effective that I manage to ignore the pain in my calf muscles long enough to squirt off-white cum onto the pure white tiles in front of me in three short but tremendously gratifying blasts.

The moment the heels of my feet touch the base of the shower, I start to come back to myself. Mechanically I lift the shower head from the cradle and rinse the tiles clean. Then I switch off the water, step out of the shower, wrap a towel around my shoulders and recover my breath leaning against the sink.

Why do I do this? I ask. My erection is no longer there to answer me and in its absence nothing I have just done makes sense any more.

I try to distract myself by towelling dry my hair, a task that doesn’t take as long as it used to, but my mind goes back to the roughly sketched women that I just pressed into service. Who they are, what they did, what I did to them, all these things break taboos or cross barriers that, in my real life I would regard as a violation and yet, what is more real in my life than those seconds of tension just before my balls unload?

The answer of course is that the man in the shower really is me but he is not really all of me. Ever since puberty I’ve lived with being someone who is sometimes driven to places he’d rather not admit visiting, much less enjoying. I’ve dealt with it by containing it; keeping it between me and my right hand. But it refuses to stay in its box. It seeps out through the cracks and leaves me covered with the snail trails of its slow escape.

Perhaps I misunderstood Onan’s sin. Perhaps it was not the repeated self-indulgence that was the sin but the increasing isolation of a diminishing self that this indulgence creates. I wonder if Onan had a wife and if he did, whether he thought of her when he spilt his seed or whether he too sought extremes that distanced his act from his reality.

Well, I know where the best of my reality lies under a duvet that’s a damn site warmer than this rapidly cooling bathroom.

I pause long enough to spray myself with the scent my wife likes the most and then head back to the bedroom.

When I slide in behind her, Claire is just surfacing from sleep. I lean into her neck and kiss her, letting myself absorb the richness of her early morning smell. She stretches like a cat as my hand slides up her warm skin and presses herself back into me when I cup her breast.

Mmm," she says. "That’s nice."

She turns over slowly so that her face is against my chest. I wrap my arm around her.

You smell nice too," she says, running her hand across my chest and down my belly.

Her lips reach my mouth at the same time that her hand cups my penis. I have a stab of concern that I will fail her; that I will stay limp in her hand, useless and insulting. I just couldn’t face that. I concentrate hard on the Claire’s lips on mine and to my immense relief, my recently used and sometimes unresponsive flesh stiffens slowly against Claire’s palm, like a fern unfurling in the sunlight.

Well, Good Morning" Claire says in a voice that tells me that it’s going to be a very good morning indeed.

Go slow," she says as she straddles me, "you’re not the only one who’s stiff in the mornings."

We both laugh. Then she kisses me. I open my mouth to speak but she puts her finger across my lips as if to say ‘later’. She moves slowly down on to my now-respectable erection. When I’m all the way inside her, she closes her eyes and smiles.

Looking up at her, I wonder how many of the mornings when I have made my way towards the shower, could have been spent like this?

I put regret aside and offer myself hope instead. For once it seems that I have led my erection rather than letting my erection lead me. This, I think, is what living with it should be about.