I've only been able to pull this off a few times... but if you are really wanting to expose your wife, it works great.
While on trips with my wife, I try to find motels with the front window & door facing the walk - your standard motel I guess. I'll eat her & fuck her until she's exhausted - then as she is falling asleep I'll tell her I'm going to stay up a little while and use my laptop, read, etc. Once I'm sure she's in a deep sleep, I'll pull the covers down - and slightly open the d****s on the front window - not too obvious, but just enough. With the table lamb positioned just right - it works perfect. The absolute best time I ever did this was just outside of Beaumont Tx in June of 07. We were on the road, dead tired & stopped at the first motel we found - one of those off the Interstate motels, restaurant, Truck Stop combos. She was too tired for sex, but I insisted & afterwards she immediately fell into a deep sleep. The setting was perfect! The bed was 5-6 feet from the window, she was partially on her side, facing the window, her makeup still on, perky 34B tits in full view, as well as her bush and legs. I pulled the covers back, tilted the lamp shade a bit & opened the curtains a few inches. Only then did I remeber where our room was situated - we were on the ground floor, near the back corner of the motel - and about 100 yards away was a back lot where truckers were parked overnight. As we unloaded our bags, I noticed truckers used the walkay in front of our room to go to the coffee shop, restaurant, etc. So, knowing mainly truckers would be passing by I got really bold & opened the curtains 3-4 inches, somewhat making it obvious I was exposing my wife. For an hour or so, there was a solid stream of truckers walking back and forth from their trucks to the restaurant getting coffee, eating, etc. Although I never revealed myself, I stood by the door trying to hear if anyone stopped at the window, etc. I guess word spread quick around the truckers, and there were several times I could hear several men whispering just outside the window, although I was never able to understand what they were saying. AND, there were several "flashes" at the window - and my cock throbbed like crazy knowing they were taking pictures of my nude wife - her legs, bush, tits AND face. After that first hour or so she stirred a bit and changed positions - lying on her tummy, her face to the window, and her ass in perfect view - it couldn't have been more perfect! It was short lived though, as she woke up and went to the bathroom - at the point I turned off the light and closed the d****s.
The next morning we went to the Restaurant and I could see several men staring at my my wife, smiling, etc. My poor wife had no idea MANY of them had seen her nude and even had pictures of her!
The only advise I'd give is be prepared to get a tap on the window or worse, a call! You might want to unplug the phone. Either way, be prepared for an explanation should you get caught! The best approach would be to tell her you were totally unaware the curtains were open, and that during her sleep, she pulled the covers off herself.