Penis size discussions on this app

Hi All, recently i was just going through a thread on this app and topic was about penis size. It seems funny to me when people post their partner has penis of 6.3inches or 7.4 inches or 8 3/4 inches. I mean how they can do these measurement? It could be 6 7 8 or whatever round to one figure at max 6.5 or 7 and half inches. How it can be that accurate that you can go multiple decimals. I just found it funny. May be someone can share their measurement story.