Volcano science project HELP - it exploded everywhere

So my 7yo wanted to do the baking soda and vinegar volcano for his school project. Seemed simple enough right? WRONG. We made it too big, used too much vinegar, and it erupted ALL over the kitchen table, floor, and somehow the ceiling?? Now I have to explain to his teacher why his project is a 4x6 poster board with dried crusty volcano residue on it. What was I thinking not doing a test run first. Anyway if anyone has tips for making this less... catastrophic... let me know for next time