Waitress Nana lives a humble life while aspiring to be a celebrity. One day she is scouted as the mascot of Moo Horns Inc. for her bust size. Knowing that all their previous mascots became celebrities, she eagerly accepts. 
 
When she is asked ideas on an advertising campaign, she can only come up with "something sexy", and adds that she is willing to do anything. 
 
The company staff interprets "sexy advertising" as porn, and so the filming begins... (Source: Fakku)

All-You-Can-Eat Cow Tits: The Animation