SERIOUSLY, WATCH STAR TREK
now more focused, she "mind melded" with shepared in the first game which alows her to share memories with others.
omg omg, i just realised this is exactly like javik with his memory thing, the protheans must have created a device to meld with OMG, THERE WAS A SPECIFIC EPISODE OF STAR TREK ENTERPRISE ABOUT THIS!!!!!! I think I just discovered something important!.
BTW, "Are minds are one"==="Embace eternity"
back to topic, she can share memories with others by doing that, here eyes turn black like that in mass effect 1 too. On earth, she is sharing her life with shepard(also some major insperation from star trek) In the most personal way possible, shephard might even be experiancing her emotions. This is simply, the closest sign of friendship that she can give.
Also, in mass effect 1 sex scene, there is no sort of biotic field like there is in mass effect 3. in my opinion, the mass effect 1 scene was just a very personal act while mass effect 3 is the actual reproduction.
also, I believe that asari do have the ability to decide if they want a baby or not. it would explain why liara said, "asari are more open about there sexuallity".
If they have the.......parts.... for physical sex but dont need them, then they would be more open. its hard to imagine for us, but a only slightly related example. did you know that whales have legs.
they can choose if they want to intitiate the actual reproduction.
in short, it wasnt sex on earth, it was if you romanced her in ME3, and they can most likely choose when they get pregnant.