'Pocketfriend', or 'Pocketfrand'.
A friend you text alot;
theoretically, lives inside your pocket/phone.
Also can be defined as: pocketwife, pocket-in-law, etc.
Note: pocket relatives do not actually have to be blood related and/or legally
married to you to qualify for pocket-relative position. You do not need to be
homosexual for a pocketspouse of the same gender.