[Coldsaturn]

Inside the Photostudio > Glint Photobooth > from the button on the left where you select Duo or just one of them, leave only the companion visibile > then from the tabs on the bottom go Pose > you'll see all the "His" poses you have currently unlocked > the one I used is the Dynamic pose "Leisure Time" (plus changed where he was looking using the orb)

For other companions the pose will look different because they all have their own way of relaxing on the sofa. For Sylus the dynamic pose is called "Weighing Options", for Caleb it's "Processing Data" etc.