"Galiano isn't connected with Attack on Pirates mission"
To Make Galiano (Submissive)
You should first answer him "Not Quite" after the Eradication of Subguhnirs.
(You will gain respect. "Respect = MC is dominant", did you get that?)
"If you didn't betray Galiano in "Battle Of Powers" there are also choices there that says; [I am not a traitor]/[Cause you like him.]
Obviously you'll choose the latter for desire/romance points.
In Clash Of Corporations, (spoiler)
'You will imprison him in the ship naked. He will ask you about a promise of which you' should say "[I promise]" and there is an intimate scene there. And choose if you want to kiss him or do something else (sorry I forgot the choices). It is sweet and wholesome.
I couldn't spoil more because Galiano is not the only one affected here in this quest.'