There are a few ways to accomplish this:
1. Eat some type of stewed meat, where it naturally has taken on moisture.
2. Find some low sugar or sugar free sauces (i.e. use a little bit of keto bbq sauce)
3. A little bit of gravy, all things considered, should be ok. Don't douse your food in gravy, but use just enough to add moisture.
4. If the meat is a good fit for it (like chicken), some avocado mash makes a nice sauce.
Really, just find something that adds moisture, so you aren't relying totally on your own saliva to help it breakdown and become mush in your mouth.