While re-reading the entire manga a little over a week ago, I was just kinda thinking that Wakana is someone that looks like she should be top but very isn't. As for Yuina, before making this comment I also remembered how some people in multiple threads elsewhere on this site comment something along the lines of "it's always the innocent-looking ones". Tho it is kinda redundant to muse about that now, this extra adds to those, particularly for the Wakana bit.