The guest sits down and your dog licks their hands, legs, and face. Some people enjoy it, others do not. Dogs lick for different reasons, so watch what is happening around the behavior rather than assuming it is affection. Is your dog loose and able to leave, or are they tense, circling, and licking while the guest keeps reaching?
Ask guests to pause petting and give the dog space. If your dog has stiffened, growled, or snapped, separate them safely and seek qualified behavior help. Do not let children put their faces near the dog. A sudden increase in licking, especially alongside other changes, is worth discussing with your veterinarian.
Offer another way to greet
Before the visitor arrives, give your dog a comfortable place away from the door. A gate lets you welcome the guest without the dog having to make contact. If your dog is relaxed and wants to approach, ask the guest to stay seated and let the dog choose. Reward your dog for standing with paws on the floor, moving away, or settling on a mat. Keep greetings brief.
If your dog licks to keep a person at arm's length, asking for more social contact will not help. If the licking is exuberant, a suitable toy to carry or a few treats scattered away from the guest can redirect the rush. Either way, the visitor may say no to contact, and the dog may walk away. Respect both choices.
The goal is a visit in which nobody has to tolerate unwanted licking and the dog can relax. For more on calm arrivals and a choice-based greeting, see the visitor and doorway guide, visitors should not have to accept licking
Sources: VCA Animal Hospitals: Why do dogs lick humans?. Dogs Trust: Dog aggression towards visitors.