In episode 3 of the TV anime, Kei and Yuri are pulled away from their vacation for duty. Kei then says to Yuri "You promised me that next time we went on vacation, we'd go topless and drive all the men wild. What happened to that?"
In the second episode of the Flash series, Lady Freya/Iris is watching Kei and Yuri in a dive bar. The two start screaming and attacking each other - and Freya glares at them, then frowns, then grimaces and shakes her head at them. Even an elite sniper/ex-Lovely Angel can't keep her composure around the Dirty Pair's antics.