[To be honest? Jiro's never even had someone grope her chest in the heat of it all before, let alone something like this - she seriously wasn't kidding when she said all she's done is "plain stuff".
But it means she doesn't have a frame of reference for what'd feel good in these regards to start with, too. Is that a good thing or a bad thing?
Well... it means, at the very least, what's going on right now is novel and exciting, just as everything else Momo's been surprising her with has been.

The little thrill she gets from finally feeling the warmth of Momo's skin against her own...]

Are you -
What?

[... Isn't nearly enough to keep her face from scrunching up, clearly upset and displeased at Momo's line of inquiry.
Without even really thinking about it, she reaches up to wrap a hand around the side of Momo's neck in a warm, almost overly fond sort of touch - rubbing her thumb gently over her jawline like that.]

Why would you think you're not?
Even forgetting all the stuff I just said I feel for you - do you think I'd even hang out with someone I don't think is cool?

And I mean, I know we're kinda polar opposites even on a good day. It's basically our shtick at this point.
That's what's good about us, if you ask me.