Subposting is sort of like subtweeting but on any platform of social media. Most people subpost with the intention of secretly talking about or referencing (typically a person) that they are angry or annoyed at without directly naming or tagging said person(s). Sometimes subposting can be in a positive manner but usually not as it is an activity usually used by passive-aggressive people.
I was subposting about Monica on Instagram after she was gossiping about me behind my back.
Its when the sussy baka is impostery in the fastion of being sus also known as suspicious formally described as amogussas moment. Knows as a moment when the sussy baka (imposter) has vented and voted out for he was a sussy imposter from fallguys