If I had to guess -
She's embarrassed over knowing what costume he'd pick [for her].
Takamine's 100% head over heels for Shirota at this point, so it at least lines up.
And she'll spin it as "I don't want to know what pervy fantasy you have in mind when you think of me", or something.
Anyway is it just me or has the artwork itself leveled up a bit? Maybe it's just because of how long it's been since the previous chapter, or the resolution of the raws or something.
Just feels more "crisp", I guess.
Thanks for the TL as well, of course.