If she'd had a clear shot of him while she and Steve kissed, she would have seen his hand move. But not out of it's place, only slowly, obviously, stroking as Steve moaned against her lips. He wasn't sure what it was about watching the two of them, but it heated his juices better than anything else.
Bucky grunted softly as Steve tugged that knot out of her swimsuit top. He knew what he'd done. And he'd done it on purpose. "Actually I might like Steve's way of thinking a liiittle better." He chuckled huskily. His hand still moved within the confines of his trunks.