I have several close friends and I have only told one (a female and it's really been to my advantage). I have two other friends that are like brothers to me. I haven't told them but I'm pretty sure they know.
As far as this whole subject is concerned I really don't think it's appropriate for people to know. For example, if I were to tickle a girls around someone who knew my fetish, they might see it as something sexual, when tickling isn't always sexual. I just feel like it's necessary so I don't look like the horny fetish boy.