And probably one of the most addictive songs in the world.
(weeaboo2): HAI, BUT SHES A TSURUPETTAN
a few seconds of silence...
(weeaboo1 and 2): KAWAAAAAAAAAIIIIIIII!!!!!
Pettan alone means flat. For example, the suffix -ko means "girl" (such as in meganeko, megane = glasses so glasses girl) so pettanko means a flat (chested) girl.
Tsuru means smooth. So smooth+flat.