Scratching is to rub a surface with a sharp object. For example, a craftsman can remove layers of old paint by scratching them off with a blade. Scratching a surface with a (hard bristled) brush is also known as scrubbing. Scratching is similar to rubbing, but in rubbing, two surfaces are rubbed against another whereas scratching involves a sharp object.
Scratching the skin, with an object or one's fingernails, causes a characteristic sensation which can be pleasant or unpleasant, depending in the circumstances. Scratching will also redden the skin. If the object is sharp enough, and/or the scratching hard enough, it can abrase or break the skin, causing bleeding. Such a thing is called a scratch.
Scratching an itchEdit
Scratching an itch typically gives immediate relief, although if the itch is caused by an irritating substance in the skin, scratching often makes the itching worse after a few seconds. Scratching an itch is a reflex frequently inherited by mammals, the so-called scratch reflex. The scratch reflex helps an organism protect and rid its body of parasites and other irritants.
Scratching in BDSM and sexEdit
In BDSM and light kinky play, partners will sometimes scratch another with their fingernails. This is often done on the back, the back of the neck, and, in men, the chest area. In BDSM, sometimes instruments such as spiked gloves are used specifically for scratching the skin. Scratching and whipping are often combined in a session as the sensation of scratching is very different and results in "reviving" an area that has become numb from whipping.
Whatever else is done, scratching always makes for an interesting change and can playfully "wake up" a partner that is too passive. As with everything, not everybody likes the sensation of scratching though.
How does scratching work?Edit
Both itching and scratching (and why scratching gives relieve to an itch) are very complex phenomena that are still not well understood. One of the leading researchers in this area, Dr. Gil Yosipovitch from Wake Forest University, Baptist Medical Centre, North Carolina, recently discovered that scratching seems to momentarily switch off areas in the brain linked with negative feelings and memories. In other words, it temporarily switches off the memory of the itch.