The first time she hugged him, she was careful. So afraid of betraying her immediate attraction to him, she was careful to clench her hands into fists she pressed against his shoulder blades. He didn't notice.
He wouldn't have, would he? She'd only done what hundreds of thousands of insecure women before her had done. Too fat, too thin, too tall, too short, too feminine, too masculine, too anything less than perfectly perfect, it didn't matter; men are the great equalizer. When faced with a man with whom she must be careful – for whatever reason – a woman will take great pains to appear not-too-invested.
And so did Sam. The first time he pulled her into a hug was celebratory. But from her first glimpse at him across the briefing room she'd felt the swift zing of attraction. So when he pulled her to him with a grin and slapped her back with vigor, even when he tucked his head into the crook of her neck and took her breath away, she clenched her fists until her nails bit into her palms before she let her hands settle against his back. Somehow, emotion travels through the fingers and it wouldn't have been safe to share that emotion with him.
It wasn't until the sixth or seventh hug that her emotions had gotten the better of her again and she once more felt the need to clench her fists before wrapping her arms around him. And so it went for a while. She'd check her emotions, learn how to enjoy him, and then something would happen – a look, a smile, a particularly Goa'uld awful day and her emotions would rise much too close to the surface and she couldn't rest her twitching fingertips upon him. Because, well, then he'd know. He'd know that she wasn't doing a very good job of maintaining a professional distance.
And then they were trapped on a ship and facing each other through a force shield and she was sure they were both going to die because the stubborn sonuvabitch wouldn't leave her behind. But then things turned out okay. For the most part. They lived, and that was something. They lived with the knowledge that they were in love with one another.
And then the next time he hugged her, when she finally had the confidence to let her fingertips press into the muscled planes of his back, his hands were clenched into fists that pressed into her ribcage.
When he pulled back she bit her lip to stem the tears that threatened to fall. And he took her hands in his and pressed them into fists held between them. He spared her a look as intense as the one they shared across a force shield. He nodded at her once, dropped her hands, then turned away.