We need some background to this quote. I was taking care of a 98-year-old man yesterday who was firmly determined to die. Not only that, he kept telling me, "Today will be the day. I am going to die. I can feel it." It was freaking me out a little. I felt much better by the time I left because, of course, he hadn't died. We had quite a few nonsensical conversations about life, but the following is the best.
My 98-year-old Patient, sitting on the commode: "This is it. I can feel it. Here it comes."
Me: "Here comes what, Sam?"
Patient: "...I am having the final defecation." (strains like he's having a baby instead of a bowel movement)