Anoushka's exam in the gynecologist chair goes very well and when it's over she's outstandingly aroused, which is why he pushes forward by fingering her pussy and even her asshole a little. That gets the teen to a place of sexual need, which is how he ends up fucking her from behind and in missionary and gets to fuck her ass.
The sight of sexy teen pussies and cute little tits turns on this perverted doc more than anything!