God, each time I pull on it, its muscle clenches.

The tension suddenly around him made her muscles clench.

Harry held himself rigid, every muscle clenched, his emotions warring within him.

The muscle in his jaw clenched tight enough for me to see it.

Fear that he wouldn't surged through him, and his muscles clenched.

His face was stony, all the muscles in it clenched with tension.

The muscles along his jaw clenched and relaxed without rhythm or purpose.

It might have been deliberate or not, but the result was the same; low down inside, her muscles clenched in instant response.

His muscles clenched at the deliberate temptation of the caress.

Steps slow and sure, he approached, his muscles clenched and ready for attack.