The feeling of the mud against your feet is getting you excited. You slide your feet around, pushing them into the soil and getting them completely covered in muck.
You cannot resist the temptation to get dirtier. You pull off your shirt and throw it aside, and shuffle out of your pants and underwear.
You fall back into the moist, pleasant mud, and make a mud-angel. You roll around, sliding all of your limbs about in the soil, and rub it over your chest and face.
Soon your hair is stiff with a coat of mud, and all of your skin is covered by a thin layer of it. You grab your dick, rubbing it, until you are hard, the pleasure gradually building, increasing, until you twist around and start fucking the soil roughly, your dick sliding in and out of the muck, and finally you cum.
You arc your back, your dick firing shot after shot of cum. But what hits your chest and dribbles from your dick doesn't feel like cum. You open your eyes, your dick still convulsing, and see it pumping load after load of grainy black soil.
You are overcome with shock and pleasure, and start humping the ground, rubbing your dick against the muck as you add to it. You gurgle in pleasure, your mouth dripping with mud, and begin oozing it from your nose and face.
What's left of your skin seems to be shrinking, melting into the mud. Your arms and legs are weak and feeble, and you manage only to roll onto your back, your dick spraying mud all over you, slowly burying you. Your features melt into an unidentifiable mess as, with one, final, massive burst, your mind flows into your dick, up and out, to spray in the air as a fountain of soil, and land on the ground.
Now you are just a mound of soil in Jack's garden. You can feel worms wriggling around inside you, and seeds on your chest slowly growing into grass. You know you should be afraid, but all you can do is relax and enjoy the sun as you harden and dry.