Hah, found one!

That's Feels Like Falling in Love, by Wendy & Tracey.

I've been wanting to use this quote <g>

Quote
"Clark, I do *not* want to grope your ch - *what* have you got on under your shirt? It's all shiny and..." She trailed off. To his satisfaction, she was looking slack-jawed. Thunderstruck, in fact.

"That's... Superman's suit, isn't it?"

"It is." He waited.

"Why are you...?" She halted. Swallowed. Blinked several times. Then, in a strangled voice, continued. "Clark, tell me you're not Superman."

"Sorry, Lois, I can't do that." With the note of amusement that had crept into his voice, he heard himself sound exactly like Superman.
laugh

"You told me you weren't like other men," she said, shaking her head at him when the storm of laughter had passed.
He grinned at her - a goofy, Clark Kent kind of a grin. "I have a gift for understatement."
"You can say that again," she told him.
"I have a...."
"Oh, shut up."

--Stardust, Caroline K