And the guy wrote 2 pages in the book just that. O.o
I wonder if he was giving some minor details too. 
Allow me to oblige your curiosity, since it's actually in Kizumonogatari, rather than Bakemonogatari (that whole first part of Bakemonogatari's first episode is basically just a trailer for Kizumonogatari):
I continued walking at a steady pace, as if pretending that I hadn't noticed her ―― and if the two of us took five more steps, we would be safely passing by each other, it happened then.
I.
Probably would never forget this moment for the rest of my life.
Without any warning ―― a wind blew from the front.
"Ah"
Without wanting to, I let out a gasp.
The front part of Hanekawa's slightly long, ten-centimeter below the knee pleated skirt was completely flipped up.
Normally, she would immediately push it down by reflex ―― but the timing was kind of bad, and both her hands were behind her back, and they were still working on the complex task of fixing her braid. Watching from my position, it looked as if she was putting on a slightly cool pose, with her hands wrapped behind her head. That's what it looked like.
That was the situation when her skirt was flipped up.
Everything under it became completely visible.
It was by no means something flashy -- however it was such elegant underwear that the eye captivated by it wasn't allowed to turn away.
It was a clean pure white.
It wasn't suggestive at all, the coverage area was actually quite large. It was the full coverage kind with thick fabric ―― absolutely nothing lascivious, and in that regard one could say it lacked sexiness.
However, I could feel the dazzling radiance of that extreme whiteness.
And it was not plain at all.
A complex design made with white thread over a white background was embroidered in the center part of it ―― for all I know there were flowers on it. That pattern, symmetric on the left and right sides, exquisitely made up the balance of the whole underwear. And the central top part of the embroidery was decorated with a small ribbon.
That ribbon further intensifies the impression of it all.
Furthermore, right above that small ribbon, her abdomen and quite a lovely belly button was visible. The skirt was so boldly flipped up that even such parts became unbecomingly exposed. You could even see the blouse's hem clearly showing tucked inside the skirt. I never thought the hem of a blouse could be so lascivious until now.
Well, the skirt's lining for me was a new thing. Despite me happening to see them, often, they were an inviolable unknown entity. For the first time I think I've understood the structure of the clothing you call a skirt.
And best of all, it was just beautiful that only the front part of a skirt was flipped up.
The pure white of the underwear, and, as if boasting a competition with that whiteness, her plump thighs, were emphasized by the contrast with the deep blue of the skirt in background, and stood out. The skirt, quite long compared to that of an ordinary girl’s, in this situation was like a curtain that highlighted an elegant work of art. The pleats in the pleated skirt also seemed as if they were velvet.
Considering her pose with her hands wrapped behind her head, it seemed as if she were boasting her underwear to me -- that was the end result for her.
She.
Hanekawa Tsubasa, in the end, didn't move an inch.
She was dumbfounded.
Her facial expression froze, while she remained in that pose, as the skirt flipped up.
I think it all happened in the space of a second.
But, I felt as if it were an hour ―― I felt like I was seeing a hallucination, where it was as if my life could be coming to an end. It is by no means an exaggeration, I experienced a whole life in a moment.
To the point where the surface of my eyeballs would dry.
The lower part of her body had stolen a glance from me.
Well, of course I understand ―― of course I understand that in this situation it would be proper courtesy to quietly look away.
Normally even I would have done so.
If I were going up the stairs and a girl were in front of me, I'd at least have the mental focus to look at my own feet.
However, I wasn't as perfect as a man to do so on the spot against this blessing which suddenly swoop down on me without any mental preparation.
It seemed as if Hanekawa's figure was burned into my retinas.
If I happened to die right now, and someone happened to implant themselves with my eyes, they'd hallucinate about Hanekawa's underwear for the rest of their lives.
That was how much of an impact it was.
An honors student's underwear.
".................."
In fact.
How long will I go on describing an honors student's panties?
When I came to my senses, Hanekawa's skirt had already come back down.
It really lasted just a moment.
There's a bit more on either side of that which is indirectly related (setting the scene etc), but actually two pages may have been a slight exaggeration. It's really hard to tell with the stupid way Baka-tsuki split all the lines up like that.
Either way, I love the humour in the Bakemonogatari series. It's so subtle, yet completely ridiculous at the same time.
