Right? I can barely fit my fingertip in there, ffs (I do have long fingernails, so I guess altogether, yeah, it's about 1/4 inch), and I have loose skin from two big babies.  And I hate the feel of things in my bellybutton. Obviously q-tips for cleaning, but I just do that because it's necessary. (My abdominal surgery some years ago cut into my bellybutton; when they stitched me back together I lost about a quarter of it, so it's very small and a little crooked now.)