If you really love your fairphone, you should carry it close to your heart 
For example in a pouch on a string/chain around your neck.
This ensures you have it quickly available if needed, you don’t miss the vibration alarm even if its silent, its out of the way without using valuable pocket-space,
and it can’t easily be stolen.
Having it in pockets, especially in trousers exposes the phone to significantly higher risks of getting stolen or damaged or lost. Also you probably don’t want such a strong source of EM radiation so close to your reproductive organs all day long. Granted no negative side effects have been proven, but … well, you know, better safe than sorry 