Originally Posted by
Utopian
Adding the glycerin to break water surface tension is exactly the same concept as touching your lathered brush to the water on top of a barber hone. Lathered soap accomplishes it quickly but alternatively you can just rub a wet finger on a puck of soap and then rub that soapy finger on top of the wet hone to accomplish the same thing. Only a very small amount is needed to break the surface tension.
If you would like a honing liquid that has more viscosity, try Smith's Honing Solution. It mixes with water so you can vary the viscosity by varying the proportion of water. Unlike a honing oil, it comes right off with water.