I totally agree, it's hard to imagine Tsuyo involved with someone outside the group, but Koichi can be so very hot with someone else. Since he can't help to be cute and in love and submitting with Tsuyoshi in my mind, there are so many images to try and explore writing him with kouhais and colleagues. Oh god, I wrote him with Wataru myself XD
(Also I stand my ground about threesomes and being watched, that could be a fabulous fantasy as long as I'm deadly sure Koichi belongs to Tsuyo and will run to him after the fun XD especially if the third is obedient and loving Tsubasa)

Yeah, the wedding was huge fun. But still fanservice, as people may say. Well, Koichi wouldn't fancy a ceremony even if being proposed properly and legally, I believe.