1.   But when he had smiled at her she had felt her stomach tighten in desire.

2.   His stomach tightened as he entered the place.

3.   His stomach tightened as he reached the doorway.

4.   His stomach tightened, his throat writhed.

5.   I felt my stomach tighten, unreason bubbling, rising.

6.   My stomach tightened to stop them.

7.   Then, as she saw who it was, her stomach tightened.

8.   Ronni felt her stomach tighten.

9.   She felt her stomach tighten.

10.   Her stomach tightened in a sharp spasm of apprehension before she half turned away, intending to close the door, only to find that her movements were frozen.