what is this

[foxydevil82]

its in your head and between your toes the more you use it the thinner it grows. What is it

[squarebear]

As well as posting the qeustion twice, you've also posted it wrong. The correct riddle is:

"You use it between your head and your toes, the more it works the thinner it grows."

The answer is a bar of soap.