-So smooth it feels frictionless, for painless anal play
-Doesn't evaporate, so less need to reapply
-Can be used underwater, such as in the shower
-Is not absorbed into the body through the rectum, so it lasts for extended anal play. I don't understand when people prefer water-based lubes for anal play, because its "more natural." Which is more natural? Something you absorb (read the label, there are alot more ingredients in there than water!) into your body, basically eating it through your butt? Or some artificial silicone that doesn't enter your blood stream, because its NOT absorbed?
On the other hand, it is harder to clean up, because it is not water-soluble. I prefer water-based lubes for vaginal play, for "natural" reasons. You know water-based will be washed right out with natural lubrication, but because silicone isn't water soluble, it could hang out awhile. (Anally, its eventually pushed out.)