What was it about her? Why did she affect him this way? He couldn't think, could only respond, and feel, and that was not like him.
River Song was kissing him.
He'd been kissed before, many times, and he'd done his share of the kissing. There'd even been people he cared about more than the usual Companion when they were kissing - like Rose, and Reinette. And now his thoughts were going in circles, all because River Song was kissing him.
And kissing him.
And he couldn't think; there were only sensations and impressions and...
soft warm lips and...
amazing bouncy hair and...
a quick and clever mind and...
smooth pale skin and...
a tiny but strong body and...
caring/aching/fear and...
… and suddenly, with a burst of clarity, he understood why he couldn't think when River kissed him. It was because for him, when River kissed him...
Time stopped.