This slug like parasite is actually a symbiote. After attaching itself to a warmblooded host, it feeds off that being. However, its tenticles, growing under the skin, act as secondary nerves, increase the victims nerve responses.
"The Cetemi have a most curious custom that in their celebrations must all men don the garb of women and women... the garb of men, to the aim that none shall... know another." -An Account of Barbarian Lands, Lord Shakthur