A super-slippery lube, silicone lasts and last for longer friction free fun.  This makes it ideal for in-the-water sex or anal play.  It's also compatible with condoms.  Because it does not break down in water, your shower or tub could become very slippery.  A little goes a long way.  A bottle of silicone lube will last a long time.  Also, never use a silicone lubricant on a silicone toy, it can cause damage to your toy.