You have to wait 6 weeks for either a vaginal or csection, because of the wound left behind by the placenta. So, nothing enters the vagina during that time to prevent infection.
As for breasts during sex, my breasts leaked all the time and I pretty much wore a bra of some kind w/ breast pads 24/7 until I stopped nursing and was fully weaned. I even wore something during sex, because honestly my breasts were huge, uncomfortable, and DH wasn't allowed anywhere near them. I was not at all comfortable letting him share them with DS.