It's called flirting. It's a social dance in which people signal possible interest and invite each other to come closer (saying, in effect, "Talk to me, let me take a closer look at you, etc. I might or might not be available"). It's a skillset that singles need to learn and practice.

But my article isn't about flirting. It's about consent. And for that, clear and direct communication is definitely required, as well as respect for boundaries.