Wiktionary
sits up
vb. (en-third-person singularsit up)
Usage examples of "sits up".
When I come out of the bathroom, the hills and valleys on the couch shift and San-xiang sits up.
Slowly he swings his feet off the cot and sits up, looking toward the half-open window opposite the fireplace.
Ryalth sits up, propping a pillow behind her against the headboard.
She sits up to take her clothes off, and as soon as we're both naked I yank her off to the couch and put her to her knees in front of me.
To lend his hands strength he sits up on her buttocks and leans his weight down through stiff arms into his thumbs and palms as they work the broad muscles and insistent bones of the spine’.
When they are about a stone's throw away, he sits up and ships the oars.