The phrase "round cheeks" is correct and usable in written English.
You can use it to describe a person's face, or to describe something that is plump or full. For example, "Her round cheeks were rosy with health."
A child's full, round cheeks.
He had round cheeks and a mop of brown hair.
Look at those round cheeks and that blond hair.
Battushig has the round cheeks of a young boy, but he is not your typical teenager.
At sixty-six, Turkson's temples are gray, but his round cheeks are still youthful.
Wilson, a former Boy Scout with round cheeks and blue eyes, speaks with a muted drawl.
Come visit us!" Verka propped her round cheek on her beet-red fist.
"What does the stringy old duck tell you?" "He says I have a round cheek," she explained with pride.
"Didn't I just say that?" She stroked his round cheek with the back of her hand.
It was 3-year-old Aylan, his round cheek pressed to the sand as if he were sleeping, except for the waves lapping his face.
Draw a perfectly round cheek on each side of her face.
