It was funny. When Barry allowed himself to think about things too much, he tended to panic and overthink it and be a total mess. But when he just went with the situation, he wasn't quite as much of a massive disaster. He might have asked Len what his age was, for the sake of fairness, but he already knew. He'd seen his files more than enough times, before he'd wiped them out, and he knew exactly how old he was. It didn't bother him, even knowing that the man had twenty years on him (was old enough to be his father, a traitorous part of his brain supplied), and he didn't really want to think too hard about why he actually found that more attractive. He had way too many pseudo-father figures to let himself think at all about how this was a very different manifestation of his daddy issues than usual.
"I don't know," Barry said with a grin. "Slow is all well and good, don't get me wrong. I appreciate taking my time as much as anyone." He returned the once over, and it really was unfair that his nemesis was so grossly attractive. "But, sometimes speed has its merit." He had planned to say more but then Len was very much in his space and he lost track of his words for a moment, just a moment, as his focus was drawn to the other man's mouth. "I mean..." Right, he had to get back on track. What was he saying? Speed. Right. The virtues thereof.
He looked up again, forcing himself to breathe as he smiled, glad that while he could no longer run, he did still have some very interesting uses for his speed. "Maybe you just haven't dealt with the right kind of fast," he said, resting his hand against Len's wrist and letting it vibrate just enough that it was obvious what was happening.
And then the moment was broken by Len's last comment, which caused Barry to burst out laughing, a shock even to himself. "Oh my god," he said. "You asshole." Nobody else had made a joke like that, and it was honestly kind of refreshing.