I found the book on DLsite here listed as おもらしピンチ!エレベーター
It's also available on other sites under the same name
You were right on it being a Sora no Shiun work though
I found the image on twitter Here
I don't know if this is the artist but their art does look fairly similar and I can't find any other posts of the image online
The artist is ごじゃるん (the @ being gojarun)
You can find the image on their pixiv profile:
https://www.pixiv.net/en/artworks/71493566#manga
(It's the fifth image down)
I don't think it's a gif but I didn't do that much searching so I may be wrong