There's apparently some Japanese folktale about a child that comes to an elderly couple in a giant peach floating down a river. It's referenced in a lot of anime.
i think part of the joke is that the ass looks like a peach
Well, it was certainly drawn like that. However, her name or nickname is "Momoga" and according to Garrus the folktale which is parodied here is called "Momotaro".
MomogaatarouAh!Help me!Please help!Um!Please!Ah- Ow!
Birds!? Don't peck meee!
Eh? Wait, not there, not there... Aaaaaah!!The end