BaliWomen's One Smooth U Ultra Light Illusion Neckline Underwire Bra, Black,36C

Q: What does the us mean in the sizing? some say 34d and others say 34d us... thanks in advance!

I can’t say for sure, but assume they mean sizing in the USA as opposed to elsewhere.

Q: Are these bras full coverage? I'm a 34DD and need the full coverage

Yesss!! I'm a 38DD & this has to be the best full coverage/full support bra I've had in years! Much better than "VS" or other more expensive ones I've purchased. It feels great! You won't regret it.

Q: Are the molded cups thick enough to provide modesty when it's cold (i.e. will nipples show?)

They are thin and flexible which I personally like. It provides some modesty but if you're worried I would buy some Petals to stick on the inside of the cups.

Q: What size insert fits best inside that won't slide?

Theres not a place to put an insert in these. If you do use any inserts it would be your boobs holding them in place. I would just order which ever cup size you wear. Hope this helped a little.