I have had a few really amazing tickling dreams - nearly always it's me tickling someone else - never really me getting tickled and not usually anyone else tickling any other third parties.
They usually involve someone I know, usually someone I'm close to and actually want to tickle (or have already tickled), but occasionally it will be someone I really have no desire to tickle eg family - these dreams have made me uncomfortable to the point where I've gradually woke up.
Occasionally they've involved celebs - I think Scarlett Johansson was one, Jelena Dokic was one and I think as a teenager I had one involving one of the female UK Gladiators
They have sometimes involved friends of mine that I've never been able to establish if they're ticklish or not, but the reactions in the dream are so vivid, realistic and personal to that person, it's almost as though I HAVE seen them get tickled before, such is the realistic nature of the laughter, things they say etc.
In contrast to the lucid dreams discussed in the other recent thread, these tickling dreams I can't really control - I've never been able to craft tickling into a lucid dream, although I've been aware of myself trying to do so - for example in my dream I'll be near someone's feet or I'll be flirting with them, they'll be shoeplaying etc and I'll be wanting to tickle them (just like I would in concious real life events), but I can't develop the dream so the tickling doesn't happen - quite often the dream comes to an end as I maybe try too hard sub-conciously to make the tickling happen.
Those dreams that have involved tickling, I don't recall any real build up to it - just the sudden tickling attack happening.
It's a wonderful feeling when you wake up from a dream like this.