A wet bottom spanking is often given on a 'naturally wet' bottom, such as when a spanking is given directly after swimming, a shower, or a bath without drying off. The buttocks can also be made wet with a sponge, a spray bottle, or similar items. If the spankee lies over the spanker's lap or an item of furniture such as a bed or couch, a towel might be placed underneath to keep the surface dry. For very 'wet and messy' types of play, in locations such as a bathroom or outdoors, a waterproof plastic or rubber sheet might be used to protect the floor or mattress.
If the spanking is lengthy, especially if it is a hand-spanking, the buttocks will dry fairly quickly from evaporation while the spanking is in progress, so it might be necessary to reapply water from time to time. Birch rods that have been soaked in water or brine are already wet by themselves, and will naturally transfer moisture to the buttocks.
Ice-cold water or ice cubes can be placed on the buttocks and left to melt, producing an interesting sensation in contrast with and to counteract the heat felt from the spanks. It can cause a goosebumps reaction, a certain numbness, help reduce swellings and can be a welcome relief at the end of a spanking.
 Why does it hurt more?
It is an observed phenomenon that a spanking on a wet bottom hurts more than on a dry bottom, but it is difficult to explain why.
One possible explanation is that the presence of water in sufficient droplets to make the buttocks "wet" (not just damp in one spot) creates a scenario where the force of the hand or spanking implement is magnified by the fact that water is not a compressible substance, and thus the droplets increase the force rather than diffusing it across the surface. This effect would only become effective if the implement is flat and reasonably wide — such as a paddle or strap for instance. A cane, switch or birch would not have much difference on a wet or dry bottom.
Another explanation put forward is that water might sensitize the nerve endings of the buttocks.
 In spanking fiction and art
In spanking fiction, wet bottom spankings are used to make a spanking scene more interesting, often emphasizing the fact that it also stings more this way.
In visual spanking art (drawing, rendered art, photography, video), showing the wetness of skin can be a challenge, as it does not look that much different from dry skin. One possibility, if the image resolution allows such detail, is to show individual drops and flow lines. Another is to use bright highlights with hard edges, rather than a soft gradient, to reflect a light source. This creates the effect of shininess and thus, wetness. Yet another way is to imply the wetness through wet clothes, puddles, splashing drops, etc.
 In corporal punishment videos
The three volume video series Caned in Wet Panties was produced in England by Playback (now 1st Choice). These were also distributed In the U.S. by California Star as part of its popular English Discipline series.
The Austrian video producer Pain4fem has made two videos, Drug Patrol and Hard Business, that feature water being sprayed on the posteriors of two girls to increase their pain while they are being severely caned.
- Normally, water is used, but a possible variation is that other substances, such as lubricant, lotion or baby oil, are used instead of water. These, however, will tend to be more 'sticky' and the droplets may splash off.
- A spanking can also be given on wet clothing, such as swimming trunks or swimming costumes. This is also said to hurt more than on dry clothing.
- Clothing that is not normally worn wet, such as normal underwear, can be made wet for a spanking that hurts just a little more while preserving the spankee's modesty.
- The implements used is wet, instead of the bottom being wet. One example is dipping a bath brush in water.