Have your child layer newspaper over his workspace.
Help him use a black marker to draw sea-inspired shapes directly on the foam sheets. Encourage him to really stretch his imagination! He doesn't just have to stick to underwater animals -- stringy kelp and bouncy bubbles also make fantastic shapes to use.
Let him use scissors to cut out all of the foam shapes.
Have him set up his painting station by placing a number of paper plates on the newspaper covered workspace.
Help your child pour different colors of paint onto each paper plate.
Show him how to press one of the foam shapes into the paint before "stamping" it down on the tablecloth.
Have him cover the entire tablecloth with these bright, beach-themed stamps.
If the tablecloth is for a specific event, consider helping your child paint a special message in the middle of the fun undersea animals and plants!