How can someone else read my Text Messages someone I know reads my text messages by tapping our phones together as in the same style of sending pictures by bluetooth.  How is this possible and how can I prevent it?
This is probably using NFC (Near Field Communication), or S Beam, both communication capabilities built into the Samsung Galaxies. They allow data transfer between devices in close proximity.

You can prevent this activity by electing to close the channels of communication.

Settings > Wireless &amp; Networks > More Settings > File/Data transfer
Turn NFC OFF
Turn S Beam OFF