I delivered an entire litter for my sister like this. They had less than an inch out I swear. Definitely open sack and be sure puppy is okay. Be sure you do not pull the puppy of course. I go ahead and clamp on the pups side. I try to also clamp and hold the placenta (with a bigger pair of hemostats)to keep it from going back in, but these times I couldn't do all (I like to be sure I have them accounted for). Anyways, clamp far enough from the baby (depending on how much length you have) I'll clamp from 1 1/2 to 2 inches if possible then cut. I usually tie around 1 inch later. Alot of people don't tie.
So, if you're not a placenta clamper (much harder with really short cords) you can clamp and cut, being sure not to pull puppy or cut mom. She'll likely deliver placenta before next pup.
This may not need to be said, but cut on the side of the clamp closest to the placenta, not puppy
