No supports needed. Just flip orientation as needed. I was stupid and too far in before I realized I designed it upside down but easy fix in a slicer. 

The bottom has channels and air inlets to allow water that drips off your wet toothbrushes/toothpaste to dry so it doesn't just sit there and mold. 

However, if you find that the water is still pooling (e.g. from the flat bases of electric toothbrushes), I also designed standoffs that allow the water to drip down into the holder to dry. These standoffs were designed for a V1 of this product but I have since changed the size so they aren't the exact size. I personally only use the standoff for the smaller section and it's too small but I'm not bothered enough to redesign it. I don't even know if the standoff for the longer section fits because I never printed it.