Bentonite clay is composed of ashes taken from volcanoes. So it does taste like mud if you wine has not cleared up. Typically waiting for 3 days helps clear up the bentonite taste. Cold crashing will help remove this taste faster. That being said, in the finished wine, one should not get any residual flavor from bentonite.
Technically. it is an absorbent aluminum phyllosilicate clay. Bentonite clay, historically, has been used in healing methods for protecting the body from various serious diseases. It contains many important metals like magnesium, calcium, etc. that heal the heart, digestive system and nervous system. People have been using the clay for various skin, medicinal and industrial purposes but eating bentonite clay is slowly becoming a health trend. Talking about how it tastes like, well, it's clay and has the same texture as any other form of fine grained clay. It is generally mixed with water and consumed.