I buy Elmer's by the gallon, pour some into a little dish, add a splash of water to thin it down a little (just a LITTLE water, or it stays wet too long), and then I use a 3" wide brush to dab it on. I just sort of punch our pounce the brush around on the batting, dab up more glue, punch punch punch, glue, punch punch punch... I can't brush it on or punch the brush down too hard or it stretches the batting so I just sort of dab it around randomly. I try to put a dab every inch or so but I'm not super methodical about it. It goes pretty quick and clean up is easy; just a little dish soap on my brush and it washes right off. I don't bother to wash the dish - when the glue is dry it peels right out.
This keeps it from being too messy and helps me not get big gobs. I used to just squeeze and drizzle but the squeezing is hard on my hands. This method is easy on all my aging parts.
