Google it!
I did. The first reference is your post in May 2017 I Think I'm Constiposted.
But then I also discovered a post on Blogger from August 2007.
But the guy has another definition:
That's when you don't post anything for a while and then all kinds of crap gets posted in a short amount of time.
Now, let's talk about the noun that describes the state of a constiposted person.
The 2007 blogger uses the word "constipostion".
In your post of 2017, you used "constpartion".
In a comment on this post, @abh12345 uses the word "constipostation".
It is essential that we agree on a common word.
By the way, I have been constiposted from February to December 2019
I remember being constiposted back then. I also remember Googling back then, discovering I had a number one hit, but realizing I didn't invent it, and failed at being a neologist.
I think I'll go with constipost now. A constipost is the result of pushing while being constiposted and there's a fine example of it here today.