Just the fantasy of wearing someone a suit, that makes you appear as someone else. This goes a bit further in stories by TheSamMoose, where people wear suits, that transform them into separate body parts, but the general idea stays the same. A really nice addition, of course, is when a character decides to wear something under the skinsuit. The difference between this here and Human Mask is that a skinsuit makes your entire body appear to be normal.
James Bond vs Susan by VanesaRubberArt
Lovely little latex crossdressing comic done by VanesaRubberArt. James Bond vs Susan by VanesaRubberArt DeviantArt DeviantArt DeviantArt