I like to imagine a senario where neul love to play with bins chest until it’s puffy and red and even leaking. Bin gets embarrassed because men aren’t ‘supposed’ to lactate and he feels like a freak, but neul gets addicted to inducing it and starts experimenting how to make more, maybe even convincing/sneaking bin some domperidone or hormones until bin gets so sore and swollen he starts coming to him and begging him to suck on his tits to help relieve the pressure.