that's a huge problem with this too. you can say there are two camps, flirting (warranted or unwarranted can be ignored) and "hitting on". i'm sure some can argue it's a subtle vs not so subtle difference

you're asking socially awkward + nervous + scared guys to 1. go out of their comfort zone and smoothly create inorganically an opportunity to strike up a conversation with someone, and 2. sprinkle in something that is considered flirtatious but not too strong that it falls under the category of "hitting on"