A friend dropped by for lunch. We were yakking on about something or other of enormous interest and importance. Yak, yak, yak, rhubarb, rhubarb, rhubarb we went while I made coffee and he leaned on the kitchen counter.
Meanwhile there was a background noise of which we were both, it subsequently transpired, subliminally aware without giving it sufficient consideration. A sort of viscous wet slapping noise. Suddenly there was a piercing scream.