why do you want to do this?
Maybe these will help
Hi Cindy, Just pour the ModPodge into your bottle, swirl it around so all the inner surface is covered, then pour the excess back into the container. You can place your bottle into a diy "sling" so the ModPodge will drip back into the container of ModPodge so you don't have to hold it the entire time. You can color the ModPodge with food coloring and when the colored ModPodge dries inside the bottle, it will have a stained glass look to it. You might want to experiment a bit with the colors first to get the shade you'll like best.
Wow excellent idea
I agree with Janice. Paint swirled around and the excess removed works the same way.
You could also try using a foam brush that you attach to a dowel to give it some length to reach inside the bottle.