Firstly, I'm not asking someone to not use their phone at all in my presence. But, when I'm with someone and they're sat there scrolling through social media for a prolonged period of time and we've arranged to meet in a social capacity i.e. having a glass of wine at theirs/mine or going for a meal etc.,
How can I politely ask them to get off their phone?
Currently, with the friends, I have a good relationship with I say in a humorous tone "don't be so anti-social" (in a kind of high pitched voice, to emphasise it's a joke) that works perfectly fine (because my friends know me and know it's not serious). But, I know there definitely is a politer way of saying it. Especially when soon I'll be moving to a new city will be making new friends who I won't have the same kind of playful banter with.
By the way, I'll only say "don't be so anti-social" to those who I know don't suffer from any form of social anxiety as it is. I know this can make some people overthink the social event that evening, and think they use their phone too much around people when it's just me that has a problem with it.
So for a bit of context as to why it can be annoying, I'm an app developer so I don't appreciate phones out of work hours as much as others do. Don't get me wrong, I'm an avid user of social media and can understand why they would keep checking it all night, but to me, we've met up in said capacity to socialise with each other to get away from the daily grind of working.
Note: I'm natively from the UK and I'm a millennial (as are most of my friends).
Update: To me this isn't a rude thing. it's really a normal thing for millennials to do, check their Instagram, Snapchat or whatever when they get a notification. It's just that I'm not a big fan of using my phone out of work because they're boring to me, I use them all day. I just want a polite alternative to the current (if out of context) rude thing of what I say. Maybe even something funny.
Also, it's really easy for someone to get distracted by technology, I do it all the time. Not because their company is boring.