No specific piercing. I'm vanilla AF, so any piercing or amount of piercing that I can't help but stare at probably means we aren't a great match.
Actual red flag ... maybe if the piercing has a swastika or other political/religious/other sentiment I find abhorrent.
Report it. IDK how terminally online the mods are in this community, but a post in the middle of the night is going to linger a while. Reporting makes it way easier for the mods and reinforces that the community still wants that rule enforced.