Yuka is Cat, Momiji is Dog, kinda why momiji called her "yukanyan".
Also, more than "following misters they don't know" I would be more worried about them being caught by misters they don't know, you know walking around naked and being stupid sexy yukkuris don't mix well...
Don't follow any Misters that you don't know you two.Ah! It's Yukanyan wafuwafu.