tickling

Tickling is a sensation that typically induces smiling, laughter, and involuntary movements. It commonly occurs in intimate relationships, such as between parents and children, or among siblings and friends. Common areas for tickling include the ribcage, armpit, and sole of the foot.1

A peculiar aspect of tickling is that it's nearly impossible to tickle oneself. This is because the brain monitors self-generated movements and anticipates the resulting sensations. When you attempt to tickle yourself, your brain recognizes your own touch and significantly reduces the sensory response, effectively "dialing down" the ticklishness. This self-monitoring mechanism prevents us from being constantly overwhelmed by our own body's sensations.1