When your having a convorsation with a guy (your the girl) and he is starring at your lips what does it mean?

I do it sometimes when somebodys talking... I just find it easier to listen/comprehend what they are saying when reading their lips and listening at the same time, rather than just staring at someones eyes and kinda not really paying attention. Now if you werent talking and hes staring at your lips.... thats pretty self explanatory... (kiss the fool)