My dog Scruff keeps on licking in my mums dog mouth and it gets really anoying .How can i get him to stop licking his mouth ?

Sorry,is that your mum's mouth or his mum's mouth,either way I suppose it means the same,just like wild dogs or wolves he will be looking for them to regurgitate the food so he can have some,disgusting but true,Sandra.

I am assuming your mothers dog is older? Often it is a subserviant gesture from a young dog to a more dominant dog , based on the youthful regurgitation

:)

Melody :)