A t-shirt and panties always worked for me. If you have a tight fitting plain top and your panties it is really sexy too. Nighties are too much effort and really can't be that comfortable. And as always you can't beat your birthday suit, it always fits the best! But don't blame me when I can't keep my hands off of you. Could be you have to deal with children around the house. Then look for short sleeve and shorts pajamas or wear a pair of boxers with your t-shirt. Keep it simple and comfortable.
Look up sexy pajamas. My opinion though. is dont show much skin.. sdress as if all your intention was to be conftarble. and also take notes on what HE wears. if you can tell he's trying to be sexy. than I guess there you have it.