That sounds just about right. Like I said, one thing that you can use as a perfect example of this is the Sonya comic that Ozzy did. That one page he did was absoultely phenominal and the lead up to it was great as well.
It doesn't have to be a bunch of panels, just like one page or so. For instance, if Sonya is being interrogated or whatever, her bellybutton would be the last thing tickled to make her give in since it's her worst spot. As you have it right now, a new person to Sonya wouldn't know that it's her outie that's pretty much certain to finish her off every time. Also, it doesn't have to be just Sonya that gets the bellybutton specific tickling.
Well, I guess it's a work in progress. You've still done a great job on it so far, but just add, at least, a little bit of bellybutton specific tickling to it in each issue and you'll become a legend in my eyes. Right up there with Ozzy.
BTW, here's an idea from me. Use other things than just feathers for tickling (i.e. fingers, electric toothbrushes, q-tips), well...for the bellybutton tickling anyway.
EDIT: Forgot to mention something. You did a good job on her outie. Very promenant and practically begs to be tickled. Good on you Deeto!