I had a failed SN attempt approximately one week ago, and it is no worse than having like a stomach bug or something. I ended up failing because I vomitted, but that was after I was unconscious. Leading up to me passing out I felt some discomfort. Kind of like my heart was gonna beat out of my chest. I'd kind of describe it as a really bad panic attack, since it kind of felt like I couldn't get enough air into my lungs, so I was taking deep breaths and my heart was racing I definitely felt pretty bad the following day, and was in bed for most of it. But I ended up going to the doctor soon to complain about "chest problems" and I didn't have any complications or permanent damage or anything. I wouldn't describe it as a good experience but compared to other methods, I found the symptoms to be manageable. On top of that, I fell unconscious relatively quickly so I didn't have to deal with the initial symptoms for very long.