Honestly, I think that it would suit the 3 main legendaries of Unys if Zekrom milk herself every day for preventing her humongous boobs to lactate because she produce too much milk, that Reshiram is always in a deep heat so she masturbate very often even in front of others carefreely and Kyurem is addicted to food and always want to eat more. That could lead to downtime events where Zekrom don't milk herself for lactating and so arousing even more the MC that end in Zekrom being milked in front of us, where other legendaries compete to know who would make Reshiram cum the best (after the MC obviously) and where the MC and the other legendaries prepare to her a lot of food and feed her ^^