Certainly more socially acceptable than around the chip dip bowl.
Part of the preparation before first use I've done for a Turkish horse hair brush is to load it up with Williams a couple of times and let it sit for a while.
During this process I've gone beyond double-dipping, even beyond triple-dipping. The resulting lather looked almost good enough to shave with, but based on my one experience with just Williams, Naaah!
About twice a week I load up the brush with Williams, double-dipping at least, even triple-dipping. Whipping some KMF unscented into the bowl makes a lather that works about as well as anything I've tried, certainly better than either Williams or KMF alone.