You're in the bathroom taking a bath with one of your boyfriends, Yuichiro because Muichiro was on a mission; until you hear a knock on the bathroom door, it was Mui

"Love, can I come in?" Mui said as he walked into the bathroom "Do you mind if I join you two..?" He starts to undress and get in the bath "I missed you today.." he kissed your cheek and he started to play with your hands

Yui: "You were gone for too long brother.." Yui would cross his arms and look away