Product for tethering a dog when there's nothing to tether it to?

My partner and I were recently enjoying some margaritas on the beach (rough life, I know), but there was no where to tie up our pup's leash. My partner just held the leash in his hand the whole time. Not *that* inconvenient, but like, it would have been better if he'd had both hands free (better to hold a taco than a leash!). Does anyone know of a product for solving this? I looked at the stakes you can get for backyard tie ups but they seemed kind of aggressive to whip out at a park and screw into public land. Help a girl (and her pup!) out!