In a medium bowl, combine the lobster meat, celery, and green onion. Stir in the mayo, and lemon juice, and toss to combine. Season to taste with salt and pepper.
Using a spoon, scoop out some of the flesh out of each avocado, leaving at least half an inch inside the skin. Reserve for another use (or just pop it into your mouth...don’t waste that precious stuff!)
Stuff each avocado have with about 1/2 cup of the lobster mixture. Serve immediately.