Matting is where a combination of hair extension hair, and your own hair clusters around the scalp, causing the bonds to intertwine with each other.
Over time more and more hair will become tangled within the matted section, slowly growing larger and larger.
At the beginning of the matting processes the hair can very easily be untangled and corrected, however the longer the hair is left, the more matted the hair will become, and the more challenging it will be to correct the problem, or to remove at the end of their wear.