He goes both ways compatriot. Boobs are just a bonus thing. Alien ladies can be interesting in their own right, but rule of thumb, never turn down the boob bonus. Who doesn't like boobs in any regard? Besides, he makes seperate versions. One that you would say fits under "canonical" and the other, not so much. Take your pick. And, on that note, actually, I believe Sangheili could use boobs for their intended purpose. Call me creepy here, but I was thinking about their jaw structure a while back, and if you coupled it with boobs, it could work. Elites can spread their mandibles wide, and I imagine one as a baby with no teeth yet could do the same. Four squeezy mandibles on boobs would probably be pretty good for getting milk. The kid would have to be at a downwards angle, rather than upright like a normal human. Milk would go downwads into the waiting throat hole, and there you go.