Recap: MBS Sunday Brunch for Sept 5

Our question of the week dealt with why wet spankings hurt more. Here are your inspired responses.

Our Bottoms Burn: Yes. I have given a few wet spankings and the spankees all said it stung more. I was given a wet bottom spanking and I think it had more sting.

You really need a helper with a squirt bottle, to quickly re-wet after every paddle pop.

Dioneo: I'm guessing that it has to do with how vibrations are less attenuated by water than by air. Think about how sounds carry further underwater. Now imagine that the sound wave as an implement colliding with a derriere. I would think the stronger vibrations are what makes it sting more, but this is all speculative.

Dano: Water tenderizes the tushy and the nerves in the skin are more sensitive.

Anne: Fisher thinks that on dry skin the air in the pores acts like an air shock on a car. Therefore, when you smack the bottom the air comes out and buffers the blow. When the skin is wet, the liquid fills the pores, removing the air which would act as the shock absorber. In addition, when the wet bottom is hit, the liquid compresses expanding the pores and increasing the nerve contact and so increasing the intensity of the feeling. That's our story and we're sticking to it!

Barely Pink: Previous posters are exactly right. The water opens the pores in the bottom, and these water-filled pores are conductors of vibration. With the water present, nerves are more receptive as well. So the whole experience is a lot more ouchy because of greater vibrations and a greater perception of pain.

D is a fan of keeping a spray bottle nearby. That evil, evil man.

Rich: Air is compressible, but water isn't. So, the energy from the hand goes straight through the water to the skin underneath, but air trapped between the hand and the bottom is compressed and absorbs some of the energy.

Of course, that takes all the romance out of it.

We should probably just agree to conclude that a wet spanking is "hotter" than one on dry skin. Maybe it's just a little kinkier. Splosh!

Michael: I think that the answer might be found within a consideration of kinetic energy and thermal conductivity. When the paddle, say, hits the bottom there is a transfer of kinetic energy into work and heat energy. The work energy moves the mass of the bottom flesh forward (flattening it) and squashes the air molecules between the skin and the blade creating a pressure wave which creates a sound (the smack). The heat energy created is transferred to the skin which raises the temperature and creates electrical energy which is transferred to the nerves under the skin.

The question thus relates to how much heat energy is transferred to the bottom compared to the work energy, out of the total kinetic energy. The skin is made up of lots of small points on the surface (the summits of the skin) and lots of depressions (the pores) and the surface area of the bottom is the total of the summits of the skin and of the areas of the depressions. There is a limited amount of summit area which is vastly increased if you add the surface of the depressions. So to transfer the heat energy effectively into the bottom you want to maximise the area exposed to the heat energy and ensure that there is high thermal conductivity in the surface.

The summits made of skin have good thermal conductivity (0.58 W/mC) and the paddle contacts directly with these summits so the energy is transferred efficiently. The transfer to the depressions has to take place firstly through the air filling the depression before it reaches the skin surface in the pore. Air has a low unit of thermal conductivity (0.024W/mC) so the transfer through air to the skin surface in the depression is poor and the whole surface of the bottom will be not receive as much transfer of heat as is possible from the overall kinetic energy in the spank. If the bottom is wetted the depressions fill with water which has a better unit of thermal conductivity of 0.6 W/mC (a bit higher than skin itself). So a good deal more heat energy will reach the skin surface in the depressions and the overall transfer of heat from the paddle is much larger. The bottom heats up considerably more and thus the spanking is more severe.

On a less scientific note the addition of glycerine to the water is said to further increase the heat of the paddling, possible because the glycerine adheres to the pore trapping the water molecules for longer and delaying evaporation.

Scunge: For me, it DOESN'T! We have tried on several occasions. My bottom, wet or dry, feels the same impact. It could be because I have a chronic disease called fibromyalgia, or it could be because I am just WEIRD!

Ronnie: Not being scientifically minded in the least, I don't have a clue. But I have to agree with the questioner. They do hurt more, but they're kind of sexy. The swats make a unique sound and the circumstances are typically different as well. Overall, wet spankings are yummy.

Keiter: On the one hand, this science behind the specialized spanking of a wet bottom is interesting. On the other hand, I really don't care why. The question made me realize that it had been far too long since this exquisite form of punishment had been utilized. I greeted my lover with breakfast in bed this morning (another thing I hadn't done for her in too long a time).

"And when you're done with eating, I'm gonna give you a bath..." I mentioned.

"I prefer showers," she replied foggily.

"I know, but this morning you'll take a bath, and stand up during it for repeated wet bottom spankings."

"Yes, sir," she smiled.

Thank you for the scientific insight. THANK YOU for the suggestion!

I salute your relentless pursuit of scientific knowledge!

Daisy: I hated science at school. Therefore, my answer is not scientific.

They just DO, OK?

I am now in awe of your readers, Bonnie, talking about kinetic whassamajig, compressions, vibrations and stuff!

Susan: These answers are very scientific, and probably right, but as a recipient I find that the temperature of the water counts. Having been scooped out of a bath many times, my hot, wet bottom does not seem to be any more sensitive to a spanking. However, the sound of palm on bum seems to be louder, and there is the added hazard of nearby hair or bath brushes!

Cold bottoms are a different matter and definitely sting far more. I suppose the nerve endings are more sensitive if I have just come out of the sea, or had an ice cold cloth applied to my rear before the spanking. After swimming, I am probably wearing a swim suit or bikini, and if this is wet it really hugs my cheeks, and I might as well be bare.

On one smarting occasion, I was wearing a thin cotton pair of tennis shorts in our garden. D made me bend over a deck chair, sprayed my bottom with the hose, and then attacked it with a table tennis bat.

I danced around the garden like a dervish after that, clutching my super smarting ice cold cheeks.

R Humphries: I am not of a scientific bent, so I am reliant upon MBJ to provide insight and observation regarding such phenomena. After all, she is the one on the receiving end. She tells me that wet spankings do not necessarily hurt more, but they have a different and entirely unique sensation.

She also informs me that during the immediate aftermath of being caned across silk pyjamas, the heat actually appears to increase rather than decrease. I have no idea of the validity of such sage observations. Perhaps the solution is for the community at large to commission a modern day equivalent of Jean Henri Fabre to conduct experimental research into matters of such import. I am sure that there would be no shortage of volunteers to act as research participants. Otherwise, I suppose we could just pour another glass of wine and continue to ponder such mysteries.

Make Mine Red: I have no idea as to the "why." I had never really thought about it much. I haven't been spanked on a wet bottom since I was 4 years old, but boy, do I remember that one well! We might have to try it again one day. Thanks for the idea!

Barbarossa: One possibility is that a wet bottom is colder, either because cold water was used to make it that way or because wet skin loses heat faster. It's well known that being hit hurts more in the cold. American footballers often comment on this.

Bonnie: If I knew the answer, I wouldn't have asked! However, I have observed that the wet spanking ouch seems to be primarily a surface of the skin phenomenon. This seems to support theories about the water adhering to the skin and transferring the force more efficiently.

Another possible answer in swimming or bathing situations is that the water softens the skin and increases its sensitivity. But as I said, I don't know.

Thank you, everyone, for sharing your scientific know-how!