Call them beforehand and say brightly 'now I know you think that you haven't room to entertain for Christmas but that's no reason why you never get a chance to shine! What would you prefer to bring, first course for everybody, or dessert for everybody? And we've all tried mum's cake and Auntie Doris's cake and my cake, but we've never had yours, so you bring that too, right?'
Then as you rise from the table, announce, still brightly, 'I'm sorry, people, but I'm afraid that this year I can't send you all home with leftovers, because I have plans for them.' They don't need to know that your plans are turkey sandwiches, turkey soup, and turkey salad on Boxing Day. Do not leave the kitchen while they are there and if they start boxing anything up, announce cheerfully, 'Oh, it's OK, I have plenty of boxes for my freezer, you don't need to use yours, you'll want to take them home.' Take the boxes from their hands, tip the contents into your own boxes, and hand theirs back, preferably unwashed.
Or you could try, when they say they have no room, "But you can cook here! You can do all the prep work at your own house, it's always easier in your own kitchen, and if you bring the turkey over on Christmas Eve and tell me what time you want me to put it in the oven, I'll do that. Then you can bring everything else on Christmas Day and I'll just keep out of your way.'
Or stack everything on top of the freezer in the utility room as soon as it leaves the table and put a padlock on the door. Hippy Hawk suggests one of those intruder alarms that screams if it's disturbed, leaning against the carcase of the turkey, and some Indiana Jones style booby-traps, but Hippy Hawk is not a member of this forum and Hippy Chick tries not to let her out much.
Other than that, I'm with weeblewobble: tell DH to cook.