When I had DS I hadn't packed my bags and had to send DH home to do it, I DO NOT recommend this :-)

I went out and bought lots of cheap but sturdy undies and that way I can chuck them if they are too gross. Also pack plastic bags to put your soiled clothes in. As for how to get around using the items I have been putting my smaller maternity clothes in the bags, like the stuff I wore mid pg as for mat bra I have 5 so I have packed 2 or 3. But last time I would pack one and wear one then wash the one I was wearing, use the one in the bag and pack the newly washed one (does that make sense)

As for toiletries I have them in a bag that stays in the bathroom and I just take them out and use them then put them back and figure if I forget them at least DH can't get that too wrong :-)