It's clearly in Aurebesh, so we're going to need a translation table1:
Now, what's tricky is that the text is upside-down, so we have to do a bit more detective work. Here's a pretty high-res shot of Poe's chest (linked to the right-side-up version):
From this, we can work out that the first word is "PULL", and that the bottom word starts "INFLA"
Now we have another image:
Where we can make out the "TO", and just enough to confirm that the last word ends with "AT", and then one more letter I can't quite make out. I'm going to make an educated guess that the last letter is an "E"
Which leaves us with:
PULL TO INFLATE
Kind of anti-climactic, really.
1 Taken from the back of a Star Wars: Rebels identification card (PDF link)