So I was in the other room and I hear the two big kids laughing up a storm, so I creep to where I can hear them better without them seeing me and this is what I hear.

Grant: Look Jena, a bottle. (he looks mysteriously excited)

Jena: bottle (she looks proud she could say the word)

Grant: We feed baby. (looks like he’s trying really hard not to bust out laughing)

Jena: *tries to take the bottle and feed the baby*

Grant: No Jena! We feed baby…(he’s about to explode…wait for it…wait for it…) IN THE BUTT!

both kids explode with laughter

Grant: BUTT MILK!!! HA HA HA HA (collapses to the floor holding his stomach he’s laughing so hard)

Jena: (looks confused, but follows along like a pro) BUTT!!! HA HA HA  BUTT!!!

they quiet down a little

Grant: BUTT!!! BUTT MILK!!! (more uproarious laughter ensues)

Jena and Grant chanting while rolling on the floor laughing: BUTT!!! BUTT MILK!!! BUTT!!

Can someone please tell me why this was funny? I mean I know why it was funny, I went to middle school. But they haven’t, how in the world? Do I even want to know? I foresee a lot more butt jokes in my future.