How to take a good boob pic laying down?

I see so many girls get AMAZING pics laying flat and taking a pic of their boobs from above but when I do it they fall to the sides and I look like a 12 year old boy even if I push them up! Is there a trick I’m missing? I’m a full C/small D so it’s not like I don’t have enough to work with 🤷🏻‍♀️