I had horrendous afterpains after my 2nd; it was a lot worse than with my first and totally shocked me. I was feeding DS a few hours after he was born and these huge contraction-style pains kicked in. I apparently turned white as a sheet and started shaking uncontrollably. From that point on, I made sure I took paracetamol regularly throughout the day and that helped a lot.
I have heard they get worse with each baby as the uterus has to work harder to shrink back. Sorry to be the bearer of bad news but I tend to think it's better to have realistic expectations. I think part of the reason I was so floored by my afterpains was that I just wasn't expecting them to be as bad as they were.
Maybe ask your midwife what sort of pain relief you can take in the first few days after the birth. Good luck, hope yours won't be too bad!