Sorry to hear about your gift/phone being stolen, anh.
I don't go to extreme measures, but I got some tips on proper pocket placement in the early 70s, when I was a security escort on cash collections in the South Bronx. I understand it has calmed down quite a bit, but the 41st Police Precinct of the New York Police Dept. (setting for the movie Fort Apache the Bronx) was in my territory. I keep my wallet, keys, etc., in front pockets. My phone is in my shirt pocket, under a buttoned flap. It's unfortunate people have to think about this sort of thing.
I believe I'll have that second mug of tea, now.