Drinking is the ingestion of a liquid; in cats, this is normally water. It comprises two components, moving the liquid into the mouth and then swallowing the liquid. To take in liquid, a cat usually places its head over the source (whether running or still) and lowers its head towards the surface. The tongue is then used in a lapping action to transport water from its source to the mouth. Lapping involves 2 actions:

1) the extension of the tongue out of the mouth into the liquid source. Extension of the tongue generally begins with a rolled tongue which flattens to increase surface area as contact is made with the liquid.

2) the bending of the tongue backwards to form an area where water can be trapped, followed by retraction of the tongue back into the mouth.

Once the water is in the mouth, the cat then swallows: in other words the water is passed from the mouth down the oesophagus to the stomach. This action is repeated several times at a relatively high frequency.
Drinking directly from a water source

The following video clips illustrate drinking from a running water source (water fountain) and drinking from a standing position (black and white cat). Cats will often drink from a crouched position and sometimes also drink from a sitting position.

The following photographic sequence illustrates the extension and retraction of the tongue while drinking from a water fountain

Mouth opens at start of drinking sequence

Rolled tongue protruding from mouth

Flattened tongue makes contact with water

Tongue scoops backwards to draw water into the mouth

Water drawn into mouth for swallowing

Drinking from paw

Some cats will utilise the paw while drinking. This may involve either pawing the water surface before or while drinking or placing the paw in the water vessel and licking the water from the paw. The licking may occur whilst the paw remains in the water source or after it has been removed from the source