Spiked gloves are a popular toy in BDSM. The top is wearing them for touching, rubbing, or massaging the bottom's skin. Due to the tiny spikes attached to the gloves, this will create intense sensations for the bottom as his/her skin is being scratched by the spikes. This kind of semi-punitive touch is very personal because of the direct contact with the top's hands, which can be used very creatively and freely. It usually makes the bottom squirm and wiggle, trying (in vain) to evade it; so this toy can be a lot of fun for a sadistic top, too.
The gloves are made of fabric, rubber, or soft leather and have tiny metal spikes glued or sewn into them, usually only at the palm and at the insides of the fingers where they are needed. The spikes should be very small, so they will only lightly scratch and tenderize the skin without penetrating into deeper skin layers. The gloves should do no more than redden the skin, similar to scrubbing with a hard-bristled bath brush, without any danger of bleeding.
Spiked gloves can be purchased at BDSM shops, or home-made. The number of spikes per glove can vary between, say, six and 30 per glove. The less spikes, they shorter they should be for safety reasons.
Usually the bottom is naked and often restrained, e.g. on a St. Andrews cross, when the spiked gloves are used. They can be used anywhere, e.g. on the back, arms, breasts, buttocks, legs, and (carefully) on the genitals.
Spiked gloves are popular early in a BDSM session to "prepare" the bottom before more painful implements, such as whips, canes or riding crops, are used. But they can also be effectively used to 'revitalise' and 'wake up' skin that has become numb from prolonged spanking or whipping.