I found this scene around 2006 I think, on the Slumberville forums. I don't know who the artist is. The filename said "Sandman", so I am going with that.

The scene shows a guy in sunglasses, placing an anesthesia mask over a blonde girl's nose and mouth. The mask delivers a nice dose of sleeping gas to the girl, causing her to fall into a nice deep sleep!

There is an unconscious carry, and some bondage in the end.

Side note: The assailant reminds me of Scott Summers, or Cyclops from X-men. It looks like the animated version of him. See the resemblence?