I just finished making 2 5-gallon watering pails with the push in style nipple waterers. I got the grommets in okay after wetting, but could not fit in the nipple into the grommet for the life of me. Then it dawned on me... dimethicone. I own a business that makes lotions, etc and have pure dimethicone. One of the most slippery substances ever. The nipples popped right in. My husband couldn't even get them to fit before and told me, "Nope, you're doing something wrong". You will find dimethicone (cyclomethicone would work also) in products like KY Jelly or some hair serums that add shine. Hope this saves someone from some sore wrists!