Belly Button Fluff 

the fluff that gets stuck in your belly button, usually yellow or blue,.. rarely red but is possible.. if you don't clean it out with a cotton bud, it stinks!and turns black and gets sticky

emily: did you see jennie's belly button fluff it's the colour of her jumper!

Belly Button Fluff by MADzzDER January 9, 2009

belly button fluff 

1) strange fabric that is found in the belly button.
2) nickname for someone who puts his finger in his belly button.
3) old skin that is inside your belly button

someone who collects belly button fluff is called: a belly button fluffer

"tibo always sticks his finger in his belly button, what a belly button fluffer."

belly button fluff by Deer John April 5, 2013