I actually wouldn’t recommend making these ahead of time. I tried to make some teeth the day before, but estimated the size of the mouth incorrectly. It’s much easier to make your teeth once you’ve carved out the jaw.
I mixed clear piping gel, red, crimson, and a drop of green food colouring and painted it over his gums to get them a bit bloody. The green helped to dull the intensity of the red colour. I didn’t want him to look like he was wearing lipstick. ;) After painting on the red piping gel, I dabbed it off with a paper towel to get that sticky, bloody texture.
I also added a bit of the red piping gel to the bottom of some of the teeth, but not all of them. He didn’t eat super recently, but also not that long ago. ;)