I stumbled across a really nice one yesterday. It's Japanese girls with an anal theme, and at the beginning of the 3rd scene, one girl deeply sniffs another girl's ass several times. So hot because you tell she did it on her own and was loving it. Then towards the end of the scene, she takes a subtle but definite sniff of her finger after it had been up the other girl's ass.

http://www.x-jav.net/2011/10/div-101...-kirihara.html

At the above link, there are links to various places to get this video... filesonic, fileserve, etc....