I'll explain it in english, a language we can all understand.
First you must have a boy. You must get either Punchitchi or Harutchi as a toddler. If you get one of those as a toddler, you have a really good chance of getting Mametchi, but not a 100% chance. When you're a toddler, play Jump or Mimic tons of times, play it until your (pencil) skill points are higher than everything else, and keep it that way. If you do that, you have a good chance of getting in the Mame family. To know you're in the Mame family, you must have either a Young Mametchi or a Young Androtchi. Once you have one of those, only play the game Shapes, that increases your (pencil) skill points, which is what you need to get a Mametchi. Make the (pencil) skill points higher than any other skills points. If I were you, I'd only increase the (pencil) skill points. If the (pencil) skill points are high, then you WILL get Mametchi. Remember, you must have a boy for all this to work.
If you have a girl, do all this but instead of Young Mametchi and Young Andortchi as your teen options you will have Young Mimitchi and Ringotchi as your teen options, and instead of Mametchi, you'll get Mimitchi.
Hope I helped!
C~M