It has become part of a "ritual" tickling my wife right there. One of the windows in our bedroom is very-high up (vaulted ceiling) Whenever she goes to open one of our bedroom windows, she has to stand up on the bed to reach it. If we are in bed and she needs to open/close it (rather frequent) then I am left with her ticklish little legs and feet right in front of me. Without fail, I reach up and tickle that same little spot, and she squirms and giggles. Most of the time, I wait for her to adjust the window first (it is hard to slide) but if I am feeling very fresh, I will reach up and give her the tiniest little strokes while she is trying to open/close the window (naturally prolonging the effort).
Best yet, she will at times stand there after she is done with the window to see how long she can take it...and stand there until she gets at least a litttle tickle. It is expected now...life is good!!