The first time I saw Jan's sister Katie, we weren't introduced, and didn't even speak to each other. I didn't know Jan that well, but she's good friends with Dana, my best friend since childhood, and Dana and I were hanging out at Jan's place drinking beers with a few other friends when Katie came downstairs on her way out for the evening. She chatted briefly with Jan in our presence, and Jan did the "Everyone, this is my sister Katie, Katie, this is everyone" thing, and then Katie smiled and waved and then went out for the night. That was it – I wasn't even sure she'd really looked at me.
I of course had noticed her. Blonde, small frame, more cute than pretty but with plenty of both. The thing that most got to me was that her face seemed to have a permanent expression of slight sassiness about it, but she didn't seem to be at all aware of it. She had a look that elicited a very specific response in me, and I must have been at least a little obvious in my distraction, because Dana certainly noticed me noticing Katie, and called me on it later that night. The two of us were the only ones who opted to continue the evening's festivities after Jan's place, and while nursing our third round of drinks at the local bar, she leaned towards me with a mischievous grin and said, "So, within how many seconds of seeing Jan's little sister were you imagining being inside her? Like six? Seven?"