when you miss the chance to use the bathroom and then become constipated. See Sienfeld, Episode 63, "The Pilot" (part 1).
the kramer effect- "I didn't make it to a private bathroom to poop when I had to go two days ago, and I haven't been able to go since."
KRAMER: (acting very bad) I saw Joe DiMaggio in Dinky Doughnuts again, but this time, I went in. (pause, stops acting) Oh! Uh, where's the bathroom?
STU: I think if you go down the hall, it's on the right at the very end.
KRAMER: Yeah. Be right back. (Kramer leaves)
(We see Kramer, groaning and holding his stomach, running down the hall, and opening the bathroom's door. Someone in there says: "Sorry buddy, full house." We then see Kramer outside leaving the building and running across the street to a restaurant: "Sorry, customers only" ...running into a movie theater: "Hey you need a ticket!" ...running through the park...)
JERRY: Hey. What happened to you yesterday?
KRAMER: I got mugged.
GEORGE: You got mugged?
KRAMER: Well, I wouldn't have minded it so much but I was running home to go to the bathroom.
JERRY: Why didn't you use the bathroom in the building?
KRAMER: It was full. I tried a few other places, you know, but that didn't work. I mean it was an emergency Jerrry. I was really percolating... So I decided to run home through the park and then these two guys they stopped me and...