We need a good laugh!
Sometimes the old practical jokes are the best. Watch what happens–no, hear what happens–when this office employee sits down for her lunch.
Alternative: if you don’t have a whoopee cushion, but you do have a table with a lot of people sitting down at it to eat, all you need is a piece of paper that no one saw you bring with you. When the person next to you sits down, rip the paper. She’ll think she split her pants or dress, acute embarrassment–but no harm done. I pulled this on my mother at a Thanksgiving dinner and the whole family got a belly laugh.