When
you don't want to go back to work/whatever else you're doing, and proceed to stay
on the toilet far too long looking at Facebook posts,
Instagram pictures, news articles, playing 2048, etc. - often far longer than it has taken you to actually poop.
This may also be due to fear of wiping in some individuals.
Poopcrastinating in its various forms:
1) I had a bunch of TPS reports I didn't want to do, so I poopcrastinated
on the toilet for a solid 20 minutes and got a new high score on
candy crush.
2) I had a huge essay to write after I finished my Econ homework, but nature called and I proceeded to
poopcrastinate for a half hour on instagram.
3) Person 1: "Where is Bob? He went to the bathroom a half an hour ago." Person 2: "He's probably poopcrastinating."