Tickling fetishism is a paraphilia in which participants erive sexual stimulation from tickling, or being tickled by, another person. Knismolagnia is the experience of sexual gratification from the act of tickling. Erotic tickling may involve the physical restraint of a submissive by a dominant. Although some consider it a BDSM activity, tickling is not fully recognised by the community and is relatively unknown in the mainstream.