Here is a great summary of what fascia is and how to train it by Prof Robert Schleip:
Training principles for fascial connective tissues: Scientific foundation and suggested practical applications
In this paper, he describes what we mean by fascia, how its definition has evolved recently, and how important it is to health and mobility. The nature of fascia is described, along with its innervation by a range of nerve types, and how best to exercise and develop fascia is offered. He also explains why various forms of exercises work well for some tissues but not all.
What is really nice, this research is not hidden behind a pay-wall. You can download it for free!