Tickleable yoga girls......
...I once went out with a girl for a short time, and her feet were so ticklish that you could not get anywhere near them. And believe me, I tried. She'd go ballistic.
One time, she was on the couch doing a yoga pose....where she became almost an "L"....her head (the back of her neck) was on the end of the couch, and the rest of her was folded back over her, so her legs (and soles) were extended way past the armrest of the couch, just hanging there.....seeing my chance, I walked over, and just lightly rested my wrist on her ankles and with the other hand started tickling. She let out gorgeous, tittering laughter....because she was completely trapped, she couldn't do a thing, she couldn't go ballistic, and just had to feel the tickling.....(plus, because there was no expectation, there was no fight)....I just spider tickled and let her laugh her beuatiful laugh. I didn't do it that long (I didn't want to break her neck!), but that was the one time I got her really nice. She just took it and laughed and laughed.