So they say there is an app for everything. Well if you're looking for casual sex then there's an app for that too! CasualX is a new app for people who want to hook up with no strings attached. They did a study to find out which cities are using CasualX the most from 1 to 10. New York came in at #1...LA #2.....Chicago #3.........where id Philly rank? #9!