Usually I go with "Is it ok if I cum in your mouth?"

Surprising her with a gooey hot shot of baby batter in her mouth could get you slapped if she doesn't allow it.

But generally her TER profile should show if she at least swallows....if she swallows it's not crazy to conclude she also allows CIM (or P411 profile if she makes the activities she enjoys visible) or read her reviews.  

This is a very newbie-ish question (imo).  

Your thoughts if any?

Or just ask.