You might see some extra scooting as if his anal glands were bothering him. The lip folds might be irritated and you notice that after he drinks he rubs his face more. The feet might get extra attention if they get wet. One thing that just occurred to me. If you are experiencing all the drought that we are getting the ground will be hard. When he urinates he might get in on his feet as it pools on the ground before it sinks in. I've seen dogs do this and they scald their pads. Chronic licking of the area causes a dermatitis that can cause the foot to become painful. Another place that yeast likes is ears, armpits and groin. If yeast is a problem with his feet, cat food or dog food with yeast in it - most do have yeast - with make it worse. Underlying health issues that are not always readily apparent will allow a proliferation of yeast and other lovely things like demodex. Then there is always boredom. My Terv is licking her front legs. It has been so hot here that we can't get her out for her usual daily run so the fronts of her legs have long reddish brown areas on the otherwise fawn coloured legs. We go through this in the winter when it is too cold for her tender tootsies and again she becomes house bound. Even though we play enrichment games with her she still needs, at the age of 11, a change of view and to stretch her legs. If she doesn't get it then she licks. Look at everything that is happening besides the foot licking and see if you can find triggers.