I mean you can't pick up vibes from snapchat or any online form of communication. You could just say whatever and give him your number and say text me sometime, then like don't message him or any contact for a week or more, leave it in his court completely. Then if he texts you act flirty. I would not judge anything really based on snapchat unless he directly asked you out over that site.
The problem today is that everyone feels like they have millions of options for dates, when in actuality people's options are more limited. You really have to stand out from the other drecks you are competing against in the dating world, on dating sites or in real life or other social media