Dude I just re-read your steps but I am SO CONFUSEDCan you rephrase it?
While talking you lock the phone? This will hang up!
English is not my native language!
When you are calling someone and the call gets connected, click the Power/lock button once, this will lock the phone, then after a few seconds click it again, this will turn off the screen thus preventing your ears/hair touching with the screen