Get closer. This might be real after all!

Pushing your way to the centre of the floor you plant yourself right in front of the couple and start dancing. Her head is back and her eyes are closed, she doesn't seem to notice you, but he looks right at you as his hand slips under her dress. His other hand slides straight to her breast, mauling her tit, showing off for you. Looking down you notice a flash of bright red. Suddenly you realise he's pushed her panties down. The skimpiest lace thong you've ever seen is stretched between her knees several inches below the hem of her dress. The guy flickers his tongue at you. You're not sure if it's a challenge, an invitation or a warning to do no more than watch.