But never let it be said that I passed up an opportunity to slip some genderfuckery into my setting, as I have decided that in this setting, ettins (of which there are probably rather fewer than a hundred in the world, so this may never actually come up) can have differing genders between the two heads, either of which can be the same or different from their genitalia (of which they have one set per ettin, Lore Sjöberg notwithstanding). Which of course leads to eight different possible combinations (though if you count "male right head, female left head" as the same as "female right head, male left head", then it's only six).
- male left head, male right head, donger
- male left head, male right head, verguba
- male left head, female right head, donger
- male left head, female right head, verguba
- female left head, male right head, donger
- female left head, male right head, verguba
- female left head, female right head, donger
- female left head, female right head, verguba
Naturally, any given ettin is willing to bang whatever (even more than the usual "90% of NPCs in Gus are bi"), because trying to navigate the murky waters of only being attracted to some set of specific combinations would be far too difficult for the feeble ettin brain to handle and would probably result in the extinction of the ettin race.
But I suppose we must now think of mammaries, as ettins seem to be mammals. Simplest solution: no ettins have enlarged mammaries like humans do (leading to the assumption among adventurers that all ettins encountered are male), but all ettins are capable of giving milk (or else the half of ettins with female genitalia can give milk). Less simple solution: each ettin either has or does not have breasts, regardless of other characteristics, doubling the number of combinations. Least simple solution: each ettin has zero, one, or two enlarged breasts, quadrupling the number of combinations. I think I'm going to go with the simplest solution.