A sexual act. Begin by having sex seated while on the toilet. While engaged in this act take a shit... when you feel yourself about ready to cum pick your partner up off you and force their head down into the toilet, now filled with your shit, expect a violent reaction, and then inject their ass, or vagina, with your load
You: "Whoa, was that lightning? It's not raining."
Your friend: "Yeah, that's weird. Oh wait! Look over there! Those tourists just photographed each other in front of that statue that's covered in pigeon shit! It was Tokyo Lightning!"