What should I do if a dog licks me?

In most cases, just wash the licked spot with water before you pray. A dog's lick does not break your wudu, and there is nothing to panic about. The stricter view (Shafi'i and Hanbali) is to wash the licked spot seven times, once with clean soil. The Hanafis wash it like any impurity until it is gone, and the Malikis consider dogs pure.

Licked skin: step by step

Don't be alarmed or rude to the dog. It is only a small ritual matter.
Go to a sink or tap and rinse the licked spot under running water.
If you follow the Shafi'i or Hanbali view, wash it seven times in total, using a little clean soil mixed with water for the first wash.
Dry the area, make wudu if you need it for prayer, and pray as normal.

The seven-wash rule comes from the hadith: "The purification of the utensil belonging to any one of you, after it is licked by a dog, lies in washing it seven times, using sand for the first time" (Sahih Muslim 279). The Shafi'i and Hanbali scholars apply the same method to skin and clothes.

What if I don't have soil?

Some scholars say that soap or another cleaning product can take the place of soil, while others say to stick to soil. If you want to follow the stricter view, you can mix a pinch of clean dirt or potting soil with water for the first wash. If you have no soil, ask a local imam which view to follow. In the Hanafi view, you just wash until no saliva is left, and in the Maliki view the washing is not required for your skin at all.

Licked clothes

If the dog licked your clothes, wash the wet patch in the same way, or change into clean clothes before prayer. If the saliva has dried and you do not know exactly where it was, wash the part you think was touched. Washing clothes in a machine is covered separately. See Does a washing machine purify najis clothes?

Licked food or drinks

If a dog licks a bowl or a utensil, the hadith says to throw away what was in it and wash the container seven times (Sahih Muslim 279). Another narration says that when a dog drinks from your vessel, you wash it seven times (Sahih al-Bukhari 172). Food that the dog did not touch is not affected.

Do I need new wudu?

No. A lick does not break wudu in any school. You only need to wash the part that was touched. That is the full picture. See Does touching a dog break my wudu? and Are dogs najis in Islam?

If you are not sure whether you have been licked, or whether a spot is still wet, you do not have to assume the worst. See Can I pray with a stain on my clothes?

Key points

A dog's lick does not break wudu; just wash the licked spot.
Shafi'i and Hanbali: seven washes, the first with clean soil (Sahih Muslim 279).
Hanafi: wash until clean. Maliki: dogs are pure.
A licked utensil is washed seven times (Sahih al-Bukhari 172).

Tip: If you often visit a home with a dog, keep a small packet of clean soil or a clay-based soap in your bag. Then you can follow the stricter view easily and still be warm to your host's pet.