With his ability to control sand, Gaara encases his opponents in a large amount of the special chakra-infused sand kept inside his gourd, immobilising them. It can be used to suffocate an opponent or in preparation for a deadlier technique, the Sand Waterfall Funeral. This appears to be Gaara's signature technique.
Trivia
Using a pun common to Gaara and his techniques, "sand binding" (砂縛, sabaku) is pronounced the same as the Japanese word for "desert" (砂漠).
