ID Millenium is simply brilliant! If you want slippery, really really slippery then this is the stuff for you!
It is very slippery & extremely long lasting, so requires washing off after use. Indeed it's that slippery that you need to exercise a degree of caution when in the bath or on tiled floors etc. Frankly ID Millenium is lush!
Caution: apart from using it on or near slippery surfaces, do not use a silicone lube with a silicone toy as a chemical reaction can damage your best toys!