This may be a 4 year old post but here it is again in 2016. My problem is support across the back. The solution that works for me is jeans that have more than one belt loop across the back. Except for a few "pricier" jeans, the major manufacturers will not do this.

My rear end and hips prevent the slide down.

To prevent a skinny jean or any fitted jean from sliding down is to buy a better quality jean. Some manufactures think that creating a jean pant without shape, in otherwords, straight from its waistband, flat in the back and sides is an adequate garment, but it is not. Whether we have shapes like rounded hips, thighs, buttocks or not, does not matter; the garment must have shape in order to fit properly. If you have room in the waistband, try putting two darts in back of the pant from the top of the waistband down about 2-3 inches on both sides (above where pockets would go). Careful not to sew darts too long to interfere with back seams or pockets. You may even have to remove the name brand tag on the waistband to do this. If you have to pay a seamstress to do this, you might as well spend the extra when buying the jean.