DEATH STRANDING DIRECTOR'S CUT

The easiest way I found -

Once you have BB (which will come very early in the story), go to your private room.

Look in the mirror over the sink, and move the right stick in any direction to pull a face. Press X to take a photo while the animation plays out: BB will give you an instant like, and your achievement will unlock.

Pretty straightforward. Bb will give a like when you do something he enjoys such as killing a bt, walking through some signs, running fast( sprinting), going fast in a vehicle even double jumping. You will probably get this without even knowing