I recently installed a (you know, one of those exposed outfits.) and I'm trying to get it on sunny smiles, but when i do, she won't wear it. I reverse pick-pocketed it, how does she wear it? is there a wait? or what?

NPCs chose what to wear depending on the DR. They'll always wear the clothing with most DR.
Going off memory here - Sunny Smiles wears a Leather Armour which has a higher DR than the prosttute outfits. In other words you can't get her to wear that outfit...

like Dudster said but their is away to do it but it requires a DLC

• do Dead Money and get a fully repaired Reinforced security outfits and pickpocket it on to sunny and take away her leather armour
  
• Then delete the DLC; this will also delete any items you have gotten from it( e.g holorifle)
  
• when you turn your Game on sunny will be in her underwear and you can pickpocket on any outfit you like

NOTE: i have not tried this on Fallout NV, so it may crash or ruin your game but it worked fine with Broken steel on fallout 3

You want to see Sunny in [censored]ty clothing *that* badly?
Surely it'd be easier to go play Tekken or something, most of those girls wear their underwear like the more skin they show = higher DT

Is there like a stun thing like the mesmetron? or something that i can use?

sadly No but in Old world blue ( the big empty) they may add one

How do you know?

I'm not afraid to admit it, yes i want sunny naked that bad.

Considering OWB is looking like it's going to be one of those 'and now we'll show you the sick crap the government was doing before the War' kind of DLC's, and with Elijah mentioning explosive collars being there, a mesmetron being there seems only suitable seeing as a collar and mesmetron went hand in hand in Fallout 3.

Excellent, my money well spent.

Then get it for PC. Mods, y'know.