To be fair, going out on a "date" is a whole lot better than going commando underneath, getting spanked a hundred times, and possibly being naked while begging on your knees, so Shibuya's reaction is kinda justified. For Akiba to be so flustered though... his perversion really took front seat before any normal gesture from falling in love.
Maybe he's faking it. Maybe it's a genuine reaction. Either way, screw that kid lmao