The act of willingly infecting your friend with an illness because they made fun of you for being sick.
Chris: "Stop being such a little bitch and go out. I remember my first cold."
Mark: "We'll see how much of a bitch I am once I infect you. I'll wait til you're wasted and share a drink with you."
Chris: "That sounds rapey."
Mark: "It is, it's flu rape."