Why do bases feel slick in nature?
This only applies in certain cases.....
Some bases can feel "slick" or slippery, but this only applies to water soluble bases (alkalis) that are relatively strong. These substances are capable of reacting with the naturally occurring oils on the surface of human skin. These oils are lipids, and contain long chain alkyl groups bonded together at one end by ester linkages.
If you consider sodium hydroxide, this reacts with the ester links to form sodium carboxylate groups, each attached to a long alkyl chain. This structure is essentially a soap (hence the name "saponification" to describe this sort of reaction). As a ressult of this, when rubbed between the fingers, the feeling is much like you experience when you rub soap solution between the fingers.