Anonymous E joined in and replied with this 2 years ago, 6 hours later, 10 hours after the original post[^][v]#1,236,469
@previous (D)
That's not a bad feeling at all, it's like a runny nose or when a cocksore starts a bleed. You're in the perfect spot to just wait and have it all wash away, you can even suds off any grease that sticks around.
Anonymous E replied with this 2 years ago, 6 hours later, 1 day after the original post[^][v]#1,236,592
@previous (F)
The meaning of the preposition "in" in this context implies that Anon D considers having diarrhea in the shower to be an even worse feeling than the OPs example of having diarrhea "post-shower".