Well I was gunna say that it's almost impossible to pick up at the gym without coming off awkwardly or like a creeper, or at least that has been my experience.
Since she does sort of follow you around on the treadmills it definitely opens up an opportunity for you to say something.
I would make a joke out of it, and be like, "Hey, I know you're just pretending to text, so you don't look socially awkward." Give her a smile and take it from there...
|