Derivative of the word Fupa. Commonly used when in the presence of someone who has a Fupa. Foopsies is used primarily when someone possessing a fupa proves how fat they are by a clumsy or irritating act. A person could then use the word foopsies as an interjection.
"Foopsies, Lisa just shat on me deek"
"Lisa just had a major foopsies when she slipped on some ice"