Slamming down legs

La

Anyone else’s baby pick their legs up and slam them down while sleeping?

We have a snoo so she’s in a sleep sack (arms out) and hooked to the bassinet. But during the night when she wakes up or in the morning she will pick her legs up and slam them down.. I call her thumper sometimes bc she does it frequently.

Anyone else’s baby do this? Is it gas? Is she uncomfortable in her bed? I have no idea..