Research coffee shops in your area that allow dogs. There's a surprising number of them out there. Spend the day typing away, maybe getting some work done on your laptop, while your dog sunbathes and takes a nice, long nap.Not only is it a great way to be both productive and social, your dog will likely enjoy the attention from strangers, and the long nap.
It's ingrained into us humans to think of all dogs as highly active and always ready for adventure. But the reality is that all dogs are different. And if your dog is super lazy, sometimes the best thing to do is to be lazy together. Grab some pillows, a blanket, and curl up with your dog to watch some movies.