Those tails are called hydrophobic. You can note the etymology: hydro= water, phobi = fear, aversion, dislike.
Phospholipds' tail is a long non polar chain, made of Carbon and Hydorgens, that rejects water (a polar solvent) and is attracted to non-polar compounds (oil for example). That is why that tails can atract dirt.
The answer is that exact locations within either cannot be determined at any given moment in time.
An electron cloud be compared with a spinning airplane propeller in the manner that in both exact location within either cannot be determined at any given moment in time.
In both electron cloud as well as spinning airplane propeller, there is a probability of finding either but exact location can not be determined.
