I think this is too far, too fast. I like this manga for not dragging shit for ages like so many others do, but this is so abrupt.
Chokki is a weirdo, but she didn't come as so daring so far, it is out of character. She was all flustered and timid only a few chapters ago and now she openly sniffs a dude — with great insistence ? In public too ? She is a japanese female and not the sukeban/gyaru kind. Females, especially Japanese, are timid, especially at that age. They're even the only country that came up with the notion of "indirect kiss". Japanese adult couples barely hold each others hands in public. Not only that, but she insists and does it AGAIN after reading — and telling the guy — about the sexual implications — out loud. I think any female realizes that doing that is the equivalent of saying "I'm in heat, mount me". Most wouldn't dare, even if the urge was there. don't know man. I wish this chapter came later, after more development of their relationship.
Edit : Made me think of the girl in this meme.