-Kit Kat bars
-a human finger
-etc (not too hard, not too soft)
Now picture this substance coming out of a homo-erectus' naughty spot (the bung cavity / choco-puddin' zone / rectum / sphinctrum-oreolis).
Finally, imagine this object smelling somewhat like a horse's baby-making-area. If one is unfamiliar with this scent, simply take a whiff after you go choco-potty (dropping the yong'uns off at le pool).
This, my friends, is Rectum Cake
Jesse: 'Yeah it stinks'
Nolan: 'Mitchell tell me you didn't just-'
Mitchell: 'Yep, I made Rectum Cake! Dig in!'
Nolan: Why did you ruin my carpet ?!?!
Michael the Happy Squirrel left the presence of Mitchell due to the spliffage of his Rectum Cake.