Tactile has to do with the sense of touch. There's a huge tactile difference between smooth glass and rough sandpaper.
Anything to do with touch can be described as tactile. Ever notice how a dog would rather sleep on a soft blanket than a rubbery leather couch? That's because dogs have tactile preferences: the softer the better. Different textures of food are tactile — they feel different in your mouth, aside from how they taste. You deal with the world of tactile things every day — you use your tactile sense whenever you touch anything.