bob up
中上級 (B2) informal
To suddenly appear, like a ball popping up out of the water.
"He disappeared beneath the waves and then bobbed up a few metres away, laughing."
文脈の中で聞く
I Cut Off a Rhino's Horn, Wrestled a 300-Pound Alligator, and Faced a Komodo Dragon
Brave Wilderness Top Videos · 94:53
these bright indicators will bob up and down,
Chaotic Couch Conversations with the Harpers
Two and a Half Men · 45:21
It's like watching your ass bob up and down in IMAX.