It’s most likely a translation thing but pretty sure calling out Hwayoung’s name alone isn’t the safe word, but rather adding “honey” or “jagiya” to it. Basically calling to him like a lover.
Why did Hina say that without any context- now I don’t even blame Masaki for taking it the wrong way （￣へ￣）
Rui was always the one who initiated things when Shion was a guy, so I don’t think that’s the problem. In this case he just got interrupted by Shion turning back. Both Ryu and Shion were playboys up until now, so Rui is most likely having a similar dilemma.
For once I wish this one was longer to flesh out some of the details.