One of the main reasons for getting a hammer drill is the ability to make substantial holes in tough masonry materials. But making deep holes can still be hard work! Burping is a technique that makes the job easier. You start the hole by drilling an inch or so. Then, you pull the drill bit back a little. Then, you drill a bit more and pull back a bit more. This continues, and the bit goes in deeper each time. The motion clears dust and debris from the hole that might otherwise clog it, and it also helps reduce heat buildup in the drill bit.