The tickling with the comb didn't really work out that well for me after I gave it a try. Perhaps I'm still doing something wrong, I'm not sure.
Nobody really touches my feet ever, so I don't even know if I'm that ticklish there. But this morning I did manage to tickle myself, with the same experience I get when e.g. a doctor is trying to examine me. It so happens that my sides are horribly ticklish. HORRIBLY.
Normally I could not tickle myself there at all, and the slightest I could get out of my fingers was a funny small sensation of "a tickle" but it wasn't anything like being tickled. More like a gentle itch? I don't know how to describe.
But I found out a way to tickle myself. Couldn't help getting quite a strong reflex as result and it went together with sound, so I wonder if my partner heard that (she was two rooms from me). I did it in the morning, after I woke up (I don't know yet if that matters) so I was fairly relaxed to begin with.
Here's how I succeeded: I moved the tips of three fingers slightly and lightly over my skin in different directions. Two fingers of my left hand and one of my right hand (I think this is important that they are different hands, and at least three different moving parts). If it didn't happen quickly I moved to a bit different spot but I didn't find it hard to find a spot that gave me quite a jolt.
Now... the idea came from something I had read: Why you can't tickle yourself. It was an article that explained that you know all the movements you make and then the signals are 'blocked out'. What you'd need to do to tickle yourself is fooling yourself, basically if your movements would be even a fraction of a second later than you make them (which you really can't do just like that) then you'd be tickling yourself. What I did is fooling myself anyway. I think I can't keep track of that many variables at the same time. When I move one finger, or two fingers of the same hand, then it doesn't tickle. But when I add the amount of movements (in different directions) from different sources simultaneously... I think my system can't keep up. Or at least it couldn't when I woke up.
It was rather interesting an experience. 😀
Thanks for the initial idea, Isabeau!