What would it be like after sarumi started dating, yatas mom insisted them coming over for a few days. And when they arive, momsaki hugs misaki and says "my son" with so much love and then w/o hesitation she hugs saru and says "my other son" with just as much love. saru & misaki's reaction?
I could almost see Yata’s mom doing that even if Fushimi and Yata weren’t dating, she clearly thinks highly of Fushimi when he’s just Yata’s friend and I think she probably has some idea of that fact that Fushimi hasn’t got much in the way of a real family. When Yata tells her that he and Fushimi are dating now she’s probably not very surprised, like she knows Yata’s had a crush on Fushimi since middle school and it’s about time those two finally got together. Yata’s still a little nervous about bringing Fushimi home though, like his mom seemed fine with it when he talked to her on the phone but who knows how she’ll be in person. Fushimi’s a little nervous too even though he’s not admitting to it, obviously there’s no point in telling his own mother (since they haven’t even talked in years) and now he’s suddenly meeting Yata’s mom not as Yata’s best friend but as Yata’s boyfriend and he’s not entirely certain that Yata’s mom won’t be upset by him somehow.
Then they get to Yata’s house and his mom greets Yata with a hug before turning to Fushimi and calling him her son too. I think Fushimi would just immediately stiffen in surprise, like his body has this automatic visceral reaction to someone calling him their son (particularly in a sincere manner, not mocking like Niki would be or cold like Kisa). Yata’s mom just strokes his hair and tells him that she’s glad to have him as part of the family. That’s when Yata finds his voice and is all embarrassed as he’s like ‘mom we haven’t gotten married yet what the hell’ and Yata’s mom just laughs and teases him a bit, like Saruhiko was in our house enough growing up what’s wrong with me calling him my son too. Yata would probably accept it pretty readily after that and in particular I can see both him and his mom smiling all fondly at Fushimi, who’s trying to recover himself and act like he doesn’t care what Yata’s mom calls him even though he’s obviously really touched. Also imagine Yata’s mom telling him that regardless of his relationship to Yata, even if they decide it doesn’t work and break up some time down the road, Yata’s mom will always think of Fushimi as part of their family. That really gets to Fushimi too, having grown up with no family and now besides Scepter 4 and Homra here he’s got Yata’s family as well, with Yata’s mom fussing over him and treating him like a child, and even as he tries to act unaffected his voice is clearly shaking as he quietly thanks her.