I just stretched one of my second holes up to 10g. It wasn't a particularly exciting stretch, and it didn't sting or anything. I put one of the sf steel eyelets in, and it keeps slipping out the back of my ear. I'm not playing with it at all, but everytime I look, the front flare is being eaten up by my ear. The flares are at least 8g (0.132 in when I measured last night), so it seems ridiculous that my ear is this stretchy, since it doesn't pinch at all when I pull it out the back of my ear.

I really like how the eyelet looks, and I don't want to get 8g ones, since my other ear is happy at 10g. Is there a way to keep the eyelet in better? Putting an o-ring on behind the flare hasn't helped.

You measured the flares, but how about the wearable? If the wearable is too short it can get sucked in, especially after a fresh stretch. 

 It's at least 5/16". It's the same wearable on my 4g colorfronts, and I've never had problems with them. The flares on my colorfronts are much bigger, though. 

if you think it's because your ear has self stretched to 8g and you'd like to stay at 10g, you could try leaving that plug out for a period of time, maybe overnight. that should tighten it up.

 maybe you could wrap some teflon tape to "hold" it in place?

  that could inadvertently stretch the hole more.

 Okay then. I'll leave them out when I sleep tonight, and see if they've shrunk a bit after my shower. If not, those GG plugs look like they'd do a better job. Thank you everyone. 

 you could slide an o-ring up behind the flare that might keep it in place