I can only recall one other instance where I asked someone I didnt know that well if they were ticklish, but again, I did it with discretion, and she didnt think anything of it.
I had once written a story on here about Kandy the Tickling Massage Therapist. (And no, Ticklish_Kandy, this is in fact a real person, and was written long before you joined this site) Anyhow, I have been for massages with Kandy the massage therapist a few times, including a couple of months ago, and, during the first session I had with her, (I had met her previously outside her massage parlor with my friend, so she wasnt a total stranger to me) I casually asked her if people ever told her massage felt ticklish, like as in when she was massaging their feet or such. She said, that yes, in fact, some people did tell her that massage felt ticklish. As I was about to get on to her massage table, for my massage, she asked me if I had any special pain or pressure points that she should be aware of. I said to her that I really didnt, but that I was very ticklish, and that if I writhed around, she wasn't necessarially hurting me, but that it might feel ticklish. I then asked her, very casually, and nonchalantly, because she makes you sign a form where if you come on to her sexually in any way, that she terminates the session, and asks you to leave. Being aware of that, I casually said to her the question in this way:" Kandy, when you have been massaged, does it ever tickle you?" Kandy apparently thought nothing of the question, because she did in fact tell me that she herself goes for massages with her own professional massuse, and that, yes, in fact, sometimes in certain parts of her body, the massage does feel ticklish. So, in doing so in such a casual manner, I was able to get Kandy the Massage Therapist to admit to me that she is ticklish, without looking like it was some big sexual question where I was trying to probe her ticklishness. I didnt cross the line, she didnt feel uncomfortable, and I didnt violate her rule, or get asked to leave.
This is what I mean by tact and discretion. Those are two detailed instances where I got away with asking people the question in the mainstream, and didnt get a dirty look, or thought of as being deviant. In truth, this is probably the only way one can get people to discuss tickling in the mainstream, in such situations.
Mitch