Aside from genetics, I think she doesn't masturbate outside of cam shows. It's why she can cum from gentle slow stroking and doesn't need to jackhammer her cock like other trans performers. It's also why she's always topped off and can cum a ton.
She also probably does kegels with how far she can squirt, stays hydrated and I'm sure takes some vitamins to enhance her output.
Sara Salazar didn't used to cum that much years ago, now she sprays cum, not thick ropes like Carolina, but cums a lot like 4+ ropes. I'm sure she's done a lot to increase her output and was maybe even influenced by Carolina. You can improve your own amount even lacking the genetics, you just need to supplement and exercise your kegel muscles.