Okay, first poo: here's my contribution of info, based on a few different experiences from friends, family and myself. (I realize for this asker, it's no longer relevant, but others will end up on this page.) This is totally TMI, but that's what this site is for. I saw so many women suffering when I researched this, that I thought I've got to get over the TMI thing and share what might help others.
~ Sitzbath - yes.
But cold water and ice works too, to numb the areas that will hurt. I got mine "free" from the hospital (let's just say no extra charge). It fits in the toilet if you put the seat up. Pharmacies might sell them or be able to order one.
~ Her partner.
Hope this goes without saying, but her partner needs to be completely supportive and quick with anything she asks for. This is not the time to complain about how difficult it is to buy maxi pads, or that he can't find things b/c she didn't clean up when she had all that time off during her pregnancy. My husband has been wonderful. For fond memories later, I wrote down all the things he has said that I will never hear again, like "Would you like me to go buy pads?"
~ Lavender is amazing for pain.
Well, more amazing than you would think. Try to get some strong smelling lavender in a fabric satchel, the kind you might get at a farmers market. Or perhaps you have a neighbor growing lavender in their yard and they would donate to the cause. Just tie it up in light fabric with a ribbon. Hold this and smell it when you feels pain. I remembered learning about lavender in my birth class with my first kid.
~ Stool softeners and magnesium citrate.
Stool softeners are generally good to take with pain killers, and one doctor in the hospital told me that more are needed if you tear. When stool softeners did not work, I wondered if I could take magnesium citrate and my doctor said it was okay.
~ Problems urinating:
Problems letting pee out are also common after pregnancy. However, believe it or not, getting the poo out might spontaneously make you pee. And being constipated will make the lack of peeing feel worse, pressure on your bladder, etc. I'm not a doctor, I'm just saying it is possible for both problems to be solved at once. (Wow, this is the most TMI thing I've ever put on the Internet.)
~ To push or not to push?
There is some debate on whether you should try to push out the first poo (stool) or let it come naturally. Instructions here are for pushing, but you can modify and not push. If you are not sure, ask your doctor.
~ Maxipad/paper towel against the stitches.
Another commenter on this site said their midwife suggested this, and I am so glad, because no medical person ever told me. I'm so thankful for the Internet! So what you do is hold a clean maxipad, or folded up papertowel against the stitches. The pad or papertowel should not be so thick that you can't feel the stitches. The idea is that it is counter pressure, so you won't bust a stitch, feel as much pain, and I think it guides the poo out. I think you want to have your fingertips on the last stitch.
~ Finally:
Put the toilet seat up, stand over it, hold the papertowel against the stiches with dominant hand, hold the satchel of lavender to your nose with other hand, squat down and push, very hard. You'll wish you had the option for an epidural. It might be a mess, but you will feel relieved. Might have to repeat a few times, maybe an hour or so later.