I think it's ok but maybe he's not getting enough water?
It's normal. My pom licks feet and floors and anything stinky really. If I could take a guess at why: It'd be that they are rat/rodent hunters. And of course, rats are very stinky, making them more attracted to licking and smelling these sort of things?
My do the same thing like yours so I need to know the same thing what you are asking so when you get the answer to it let me know by sending it on here also?