It's kinda funny that Renko's idea on how to calm and spoil Merry is to give her some of her boobs, even though she's technically the "flattest" of the two (and that in the post page, Renko seems to be jealous of Merry's breast's).
It's kinda makes me think that Renko hasn't watched a lot of +18 works to understand what or how to start sex with someone of the same sex like Merry, so boobs are very much the first thing it's comes to her mind..