Maybe you do this already - sleep naked. Once you have tried it you won't want to go back to night clothes. Another possibility is to put a fully charged vibrator in your pussy and leave it switched on until the battery runs down.
No offence intended Ollygrumps but outside of the UK where the night time temperatures are nice and balmy most of us sleep naked anyway!
The vibrator idea is ok if a little predictable, actually butt plugs seem to be a better alternative for over night as they stay in place and there is definitely something slutty about a girl having her ass full all night.
My suggestion would be to try for a set of sleep underwear, specially picked and modified for best effect. A bra with nipple cut outs (or an old one with the nipple area snipped out) is surprisingly effective at night. There is an odd thing that happens when you wear clothing like this, the body normally gets used to contact from your clothing within a few seconds and you don't notice it any more. However when you have unexpected contact through holes in the clothing the body reacts with extra sensitivity. So at night movement of the sheets or blankets over your exposed nipples (but covered tits) you will find extra stimulating.
Team this with a pair of panties pulled nice and tight into a wedgie and you have your sleep wear for the next few days.
Finally top the whole thing off with a quick game of "Edge dice" and you are ready for slutty sleep. Oh, what is Edge dice? Take one regular die, roll it, the number you get is the number of times you must masturbate to edge before going to sleep. If you roll a 6 on the 6th time you get to cum! Do this with your wedgie panties tightly in pace to make sure they get nice and wet. After a few nights of this they will be the sluttiest panties you own!