1. The act of two people flirting/getting intimate, can refer to one-sided sexual quidditch.
2. Refers to a person playing 'mind games' with another person.
1. Robert and Dahlia had been playing sexual quidditch all day, and the rest of us wondered whether they would hook up when we left the room.
2. Stacy had been playing sexual quidditch with my emotions all day; when I acted upon it she denied my return sexual quidditch.