There are quite a few places to get anal in the game. Which part of the walkthrough are you on?
I'm on Hangar bay 01
In that scene, you already need to have the Taboo kink to get the Anal kink. If you do, you'll see a fantasy when you tell Cole to screw himself - it'll give you some options, so choose 'Backdoor in the Backcountry' to get Anal.
