[Shikijin]

Originally Posted by Rhythm

Spoiler for Ep. 11 @ around 10:26:

Nadeko: Koyomi-oniichan, you always follow up on my jokes perfectly! *Starts clapping/smiling*
Araragi: [Heartbeat sfx] *Reaches out towards here face and tries to grab it?*
Nadeko: *Avoids* W-What is it?
Araragi: Nothing... Really....[Heartbeat sfx] *Lifts up her skirt a little and holds it there for a few seconds* *Falls back to wall* I feel like my manhood is being measured when I'm around you.
Nadeko: Hmm?
Araragi: Don't worry about it.

Not sure what this is about exactly.

This is explained in the novel, but not in the anime. In the novel Sengoku has the hair covering her eyes, so much that Araragi even doubts she can actually see well. So he tries to touch her hair to test it, but for Sengoku the hair is the "place to guard", so she dodges Araragi's hand with surprisingly quick movements. Then Araragi tries the opposite side, and grabs her skirt. No reaction at all from Sengoku, because she only cares about her hair. Araragi though understands flipping up her skirt is not very manly, so he desists.

EDIT: to be exact, it's the forelocks that she cares the most.