Gasping for Breath
When you drop a long-ass shit -- so long, that the tapered head sticks out of the water and then is reluctant to go all the way down right away when you flush.
Tom: Dick, look at the long-ass shit I just dropped. (Flush --)
Dick: It won't go all the way down -- it's gasping for breath.
Dick: It won't go all the way down -- it's gasping for breath.