Really...This girl's scary~Why's she even coming out to me on this kind of thing anyway?Osaka, ya'know? Okonomiyaki's our bit on the side!Eh? Why? That's food, right? Are Osakans getting turned on by food now? No... They couldn't be.. jamming it into okonomiyaki....? No matter how you look at it, that's gonna burn......Okonomiyaki is their bit on the side?/okazu/ both 'side dish', as in a thing that one has as an accompaniment to a main meal; and 'wank material', something to get your engine revving for some solo action.
'Bit on the side' is a British term referring to someone who you have a adulterous sexual relationship with (usually not a serious one)