In surfing there's a technical term for stealing somebody else's wave. It's called shoulder-surfing. It's very rude and surfers really don’t like it.
However, if you're taking money out of an ATM you should be really careful that nobody is standing too close behind you. They may be shoulder-surfing, that’s looking over your shoulder trying to watch you enter your personal code.
Shoulder-surfing might also have another meaning. You know when you are at a party, talking to someone, and they don’t seem to be very interested in your conversation? They seem to be constantly looking over your shoulder, trying to find someone more interesting or attractive to talk to. They want to upgrade to someone better – some people call this shoulder-surfing too.
Wait for more tips to brush up on your English!