For the poison type legends when they get to the milk tasting part their milk could have said to taste like alcohol since when you go to a bar and could be asked "pick your poison" so the legend could say "Want a glass, bottle or drink directly from the TAP". Also since poison types are highly resistant to poison they could drink as much alcohol and really never get drunk fast enough to affect them and same is said for their children so it would be fine on them to drink it. Could even be said to bottle it and let it age to a higher quality if the ship was to have a mini bar for fun. There is a wine called "Milk Wine"
You could even have it that fire types are weak to water so when they get covered in the MC cum could be a critical hit to them and heighten there orgasm.