Nutella Bella or "Nubella" is the term used after anal sex where the end of the male genitalia (bell) has been covered in the delicious chocolate spread of nutella (In this context shit) creating a Nutella Bella.
A young man has just had his first encounter of anal sex unfortunatly his partner had forgotten to Anally douche.
"Crikey, there's poop on me bell!" (Tastes some) "Mmm it's kinda like nutella"
Hey!! Nutella bella!!