When a lunch box is stolen, the contents are eaten by the thief and replaced by him or her taking a nice warm shit inside the box. The lunch box is then returned to the owner for a nice lunch time suprise.
Little Billy was starving when he got home from school because someone gave him a dirty lunch box.
The dirty lunchbox is an act in which one participates in the lunging of large fruit such as whole pineapples, pumpkins, or watermelons and jamming them with much force and stamina into ones partners anal hole. Once you have jammed the fruit as far as you could into the anal hole you leave it in there and have sex with the girl. Once she can no longer take it you take you dick from the vagina and insert in in the asshole and drop your load on the fruit. You are left with a bloody, cummy mess you unback your lunch and feed it to the girl. Once she has finished it all you smack her across the face and you say you forgot to pray before eating your lunch and she must now receive dirty communion.
Your mother forgot to pack a lunch today for work, don't worry I was nice enough to give her a dirty lunchbox, trust me I don't think she be wanting to eat for a while.