How to make skyr more fluid
Skyr is a milk-based product that is thickened with lactobacillae and similar bacteria and sometimes rennet. It falls in the same category as yogurt and quark.

For thinning, use either water or milk (possbly cream for a richer taste), the latter keeping a more "milky" taste. Wikipedia states:


  In its traditional use, it was diluted with water when used as a beverage, or mixed with milk and crumbs of flat-bread as a quick meal.


If you want to use skyr for hot foods or sauces, be careful. Like yogurt it won't take heating too well and is likely to separate or curdle.