He's assuming she's being straightforward like any normal guy would.
*snicker* *snicker* Senpai. I'm not wearing a bra today.
Loook... I'll show youuu!*snicker* *snicker* Look, I'm not tanned around here, so my skin is pure white. Senpai, it's the same color as your skin, right?Huh? Senpai? You are nervously looking away? Please look here properly.
