1) A fear of interrelating with others. People are often; a) afraid to 'come out' about their attraction to SM out of fear of societal repercussions, or b) they may think that no one shares their attraction to a particular SM (or other sexual) practice. In both cases, this can lead to feelings of inadequacy, self-doubt, depression, and/or loneliness.
2) A technique of sensory deprivation, bondage, and trickery to make a submissive feel as though he or she is being left alone.