This is what you need:
You will obtain a slightly similar effect if you use a high backed chair with a headrest. Leather might be the best material, as theoretically it will absorb less of the sound waves. Rest your head against the headrest and you will, if you're perceptive, notice a difference somewhat akin to the cupped hand to ear. However, it's not nearly as intense. The back of my chair is high enough to rest my head against, however most of the time I listen with my head away from it.
However, be aware that you are not hearing the music the most naturally, with the unaided ear, but rather a slightly modified/distorted form, similar to echoes from the back of an arena heard during a concert. I prefer not to have that effect most of the time. Of course, if you enjoy it, who cares? It's your rig, your ears, your fun! :)
If the Batphones are designer, then you may be better off spending your money on the chair! :)
I remember that years ago some vendor offered 'ears' that you put on your ears to create the 'granny' effect. What it told us, proven by many research projects that are done in the hearing aid field, is that the shape and contours of each person's ears will make a difference in what they hear. Ideally, a set of Obama ears will provide a better hearing experience, not that I believe he ever 'listens'.
Is it me, or is there no mention anywhere in the link provided by Mofi or on the Yanko Designs website if these Batphone Ear Extensions are actually for sale? I want to buy a pair and crack up my colleague. I do have a problem with my one co-worker who speaks so darn softly I am always asking her to repeat herself. I want to pop into her office one day with these on.
PS - whether I am deaf and in denial or not, I like my system as is and do not like high-backed listening chairs.
When I was searching for a listening chair years ago some unorthodox types seemed at first blush inviting. I thought stressless chairs might be very enjoyable. However, I saw that they inclined the body such that the ears were not in optimum position for listening, so they were rejected. It can be a task to find a chair which is comfortable but does not put you to sleep. I certainly would not enjoy a chair which every time I sat down to listen knocked me out! I want to be alert, not anesthetized. I put enough time/money into systems that I want to hear them, not sleep through their performance. So, beware a chair that is TOO cushy.
I find that I can live with a chair that is a touch less cushy if it has an ottoman. Putting my feet up is as important to relaxation as anything. :)