I called the Permatex company and spoke with a man who explained the wicking action to me. It is referring to the silicone activly filling gaps when being applied. He said that sometimes if there is a large enough gap, you can come back and need to put more silicone on because the silicone has crawled into the void.
I told him that I was using it to seal a tarp, and he told me that he thought it would be perfect. I also explained how his product was competing with the regular silicone because you have to thin it, and he said he felt it was harmful to the silicone to dilute it because it would weaken the bond.
Hope this helps!