You have probably seen some nice pictures online of barbed wire on models posed for effect but its not for the novice.
Barbed wire is a tricky thing to use mostly because the base wire is so rigid, it isn't designed for tight wrapping such as you suggest. The core is usually a hardened wire designed to be put under high tension stretched between posts. Most products sold for domestic use are required by law (in Australia anyway) to limit injury and as such the points are not really sharp and tend make dents or if applied very hard blunt puncture wounds. These are skin tears and as such more difficult to keep clean and heal.