Just make your intentions clear in your messages if you don't want to feel like a dick like, hey just here for the summer so not sure I want anything serious but I'd love to hang out. Hi Will, not sure how many women send you messages, but here goes. No pressure, right? As for how to approach potential hookup partners you've matched with, transparency and manners are important, as always.
Your messages should be fun and a little risky to send, thats the line.