Step 1: Sign out of Skype and other applications to where a person may grab your I.P.
Step 2: Type in '192.168.1.1' or '192.168.0.1' in your address bar. A login screen should come up, which is to your router.
Step 3: Login under the Username: admin or Admin, Password: Password1, Password, password, password1, admin, admin1. If none of those passwords work look on the back of your router.
Step 4: Once logged in, head over to advanced options.
Step 5: Select something along the lines that has to do with a MAC Address
Step 6: Change a few numbers in the MAC ADDRESS then click apply or save
Step 7: Hop on a VPN and sign back into the application where he was grabbing your I.P. from.