There are a number of reasons a dog will lick, so it’s very difficult to correctly say why your dog is doing it without seeing the full context of the situation. Below are the most common reasons that dogs lick:
It could be the salt/taste on your skin (especially if it’s hot or you’ve been handling food).
It could be that he/she’s doing it seeing themselves as affectionately serving you – keeping you clean as your submissive (if you have indeed been following the Amichien Bonding method of showing your dog that you are the pack leader).
It’s also possible (if you haven’t been following it!) that they could also see themselves as affectionately keeping you clean as your superior (parental figure)!
If a dog is licking a carpet/sofa briefly that can be them trying to clean their tongue.
Some dogs lick out of stress. E.g. obsessively licking something and not stopping easily. This is quite easy to identify, as often they will lick for an exceptionally long period of time. If they are licking themselves, this may result in a sore appearing, or it may also involve some chewing. If they are licking you, you may noticed a fixated look on their face and a furrowed brow. If you are noticing this, please get in touch as your dog would really benefit from you seeking some help on their behalf.
Should you allow your dog to lick you?
It’s not something I like, personally speaking (because I know where else they lick!) so I stop it – but it’s quite a normal, harmless behaviour, as long as it’s not the stress related version. The thing to be clear on is whether the licking is on their terms or yours. I.e. did you call them over and then they started licking (okay), or did they come over on their terms and start licking you (they are in charge).