Works for me every time, youhave 3 finger prints you can asign, use the thumb you unlock for all three doing them in different angles, even switch the angle up on every swipe when setting one print up, figure out the motion you would normally use to unlock it and try setting it up that way.I actually set my right thumb up for 2 of the the 3rd I used my left thumb just in case I'm holding the phone in my left hand, but you don't need to swipe your thumb vertically down, as long as your swiping the whole button it should be good, start with your thumb horizontal and move it a little counter clockwise each time till set up is done.works lawless for me unless I'm at work and my finger is dirty, witch is good because it knows, it's very accurate if set up properly., hope that helps
SENT FROM DJMOUSES SM-G900A