yes i actually have a gf who i completely aware of my belly button fetish due to just this!
she is a super pretty fit blonde and we have been hooking up for awhile, was at her apartment around last Christmas and was helping her set up the tree and she was wearing a white sweater and black leggings. as we were setting up the tree i noticed her sweater was on the shorter side and as i was putting an ornament on the tree to her right, she reached up to put the star on top (smaller tree) and her sweater came up like 4 inches and her belly button was in my face. i immedietly told her (nice belly tease) and poked it, she laughed and said "oh, oopse lol this sweater is cropped"
her and i joke about it from time to time still and id hope to see it again like that
