A fascinating cat fact
Licking fur that you've stroked or petted. This can be misinterpreted by owners as the cat rather waspishly washing and tidying sullied and disordered fur, but in fact the cat is responding affectionately to the scent you've left there- tasting you, as it were. Secondarily, s/he is indeed ordering the ruffled fur; while third purpose is to remove some of the scent you've left so that the dominant odour is once more cat's own.
From the book CATS facts, figures & fun by Eve Devereux