noun
belly crawl; commando crawl
Refers to a baby's crawling style where the belly stays on the floor, dragging the body forward with the arms. Common in parenting and child development contexts.
うちの子はまだずりばいしかできない。
Our baby can still only do the belly crawl.
ずりばいの時期はあっという間に過ぎる。
The belly-crawling stage passes in the blink of an eye.
ハイハイ is the standard hands-and-knees crawl, while ずりばい is the earlier belly-dragging crawl.
From ずり (ずる, 'to slide or drag') + 這い (はう, 'to crawl'). The exact derivation is uncertain, but it describes the dragging motion of a baby's belly crawl.