As you tap, you unlock "stories" and outfits for your mayo jar, ranging from bikinis to cat costumes.
It sounds like you're diving into the legendary clicking experience that is My Name is Mayo . If you've got your hands on a specific build (like that .rar file mentioned), you're likely looking for that notoriously easy Platinum trophy or just some mindless tapping fun. My.Name.is.Mayo.Build.2840766.rar
You literally just tap the jar. On consoles, players often mash the X button and the touchpad simultaneously to speed it up. As you tap, you unlock "stories" and outfits