When I purchased a new photo editing software a while back, I tried it out by playing with a photo of my wife hugging a friend. She was hugging him from the side, as he was facing front with his hand on her lower back. she was wearing a short skirt where her panties were just barely showing, as she reached up to give him a hug.
Just a couple of operations later, the little bit of panties disappeared. Little by little the skirt disappeared as more and more of her hips was shown. The exposure went higher on her hips so if she was wearing any kind bottom, it would have shown when it went around her waist. Basically I lifted the side of her skirt and *removed her panties.
I had saved the gradual lifting/removing in a series of pictures, then put them back together in a GIF file. Playing the GIF to see her hips being exposed gradually. Very sexy to play that in a loop to fit the title of this thread.
A while later I added version 2 by taking his hand from high on her waist, then repositioning down to her hips after that was exposed. Repositioning his hand multiple times all over her bottom just like he was groping her. The resulting GIF is VERY entertaining as I loop it over and over again.
I am thinking about refining making version 1.1 where his hand is there as her skirt is slowly lifted higher and higher. Then adding back version 2 for him to grope her exposed hips.
Oh yes, I do masturbate to my wife's pictures specially with *enhancements.

btw: Tried repositioning the hand on her boob, but the angle was all wrong looked horrible.