Scarleteen

i'm sure this is normal, but i just wonder why it's harder to move my fingers inside her when she's telling me that it feels good, and how i can continue to provide the same sensation while it's harder to move.

Hi! This could be because either she's starting to orgasm, which causes your pelvic muscles to contract, or she's just contracting her muscles perhaps not realizing she's doing it, which can also happen in this scenario. Have you asked her if it feels any different? If she's saying it feels good, I'm not sure you need to switch anything up. Or is the issue that it's physically hard for you to move your fingers?