File sharing authentication

When I access a folder shared on another Windows PC, I'm prompted to login
with and user and password of that PC. When I login, the folder is
accessible, until I shut down the client or disconnect the user. I want to
manually logout from the shared folder! How do I do?

This is my typical scenario: I want to access my files from another person's
computer, but I don't want my folder is still accessible to that person when
I've finished!