There is so much watermelon to go around, can the dog help you finish it off? Yes! but there are a few safety concerns to note. The watermelon rind is not a chew toy and should not be given to dogs to chew on or eat. Chunks of the rind can cause stomach upset and can cause an intestinal blockage. A blockage can mean emergency surgery, so please don't take that chance.
Watermelon seeds are also not-so-good for dogs to eat. Watermelon seeds cannot be digested, so they can cause intestinal damage, intestinal blockage or just stomach upset. If you don't mind removing both the rind and seeds and feeding just the pink stuff, then a summer picnic can include the dog...at least when it comes to your watermelon dessert.