ts'uulba̱ksk [ts'uul/*ba̱ksk]
intransitive verb. duck down; sink down
../mp3s/ts'/ts'uulbaksk-dl-hb-03.mp3 Sa ts'uulba̱ksga üüla a la̱x aks. The seal suddenly ducked down in the water.

Bibliographic sources: Dunn, Practical Dictionary entry: 1974.
Source: Draft Dictionary entry.