Well, I guess this is as good a place as any to explain Erra's possible crew xpac and shove all the ideas I had for it together in one spot, preggo content included.
Alright, so a long while after Erra and Steele become lovers, Erra will be carrying an EXTREMELY INCONSPICUOUS shipment towards Tavros from a rush planet to be handed off to Reaper techs there. Though on the course of her journey she will be waylaid by pirates (who might have been contracted by KihaCorp >.>) and go down somewhere over Tarkus. Both she and Dee will survive the crash, and Dee will send a distress signal to Reaper. Once Reaper finds out their EXTREMELY INCONSPICUOUS shipment has been compromised, they'll send in the goons to eliminate Erra and retrieve Dee for a memory wipe. Erra, seeing Steele as one of the couple people in her life she can trust, will send a distress signal asking for help.
Steele goes to help her, shoot up some goons, investigate that shipment filled with precursor technology, and rescue Dee in the process. Once all is said and done Erra asks Dee to set the ship's warp core to overload and they all fly out of there with Steele, leaving nothing behind for Reaper.
Of course, now Erra is out of a job, ship, and needs to lay low for a bit, and although she doesn't enjoy not being the one in control (outside the bedroom), she'll happily join Steele's crew, because she's still a bit fucked up in all her emotion bits.
During her time aboard Steele's crew their relationship will develop a bit (she'll also get a SteeleTech jumpsuit and swoon over Anno a bit because something about ausar pet-playing with other ausar just clicks with her puppy-brain), and eventually lead to some sort of missionary + belly rubs scene where Steele might say some "I love you" things. Later Erra will ask Steele if they meant those things and they can pass it off as heat-of-the-moment, and have their relationship continue as normal (although it won't be as crippling a blow as the initial relationship would be, it'll still hurt her a bit). If Steele says they meant those things, it'll make Erra so happy she'll be brought to tears, because it's been so long since someone told her they love her, and will lead to a very emotionally-vulnerable Erra.
This is where pregnancy comes in: if Steele wants, they can continue to have Erra be a pet-play loving, spunky, slightly-more happy ausar, but if they want Erra pregnancy, they'll need a broken Erra, a perma-puppying of sorts. Steele will be able to subtly start treating her like a puppy outside of sex until Erra is convinced all she wants to do is be Steele's happy, whiny, needy puppy. So after that, Erra won't really be Erra and it would be very easy to suggest that she become your little breeding-bitch, crawling around your nursery with her tummy swollen full of your pups.
Yeah, that's the general idea anyway, if any of this ever happens of course.
Oh! And if you reject Erra originally, she'll die alone and unloved, buried by the winds and swirling rust-storms of Tarkus' scrap fields. Dee will be retrieved by Reaper and receive a memory wipe, but it'd be cool to have her show up in some sort of Reaper installation later in the game: same voice and mannerisms, no memory of her captain.