Hi lovely! I’ve just had my op 6 days ago, I’m naturally flat on top and bottom heavy so upper boob was really important to me and I mentioned I didn’t mind a little bit of the fake look, as I didn’t want them looking too natural or droopy! He explained to me that under the muscle requires cutting your pectoral and placing the implant underneath, so the muscle is essentially flattening it in place slightly (so you get a slight slope at the top)! Over the muscle you achieve more of a rounded look up top, which is what I wanted so that’s what I went with, I also train so over the muscle was a better option for me as I had enough breast tissue! Hope this helps! Xx