Are you using a liquid yeast culture or a dry yeast? If you're using dry, rehydrate it in about a cup of room temperature water before you pitch. Again, if you have a funnel, put it in the neck of the carboy and pour the liquid yeast or the rehydrated dry yeast slurry into the funnel. Once you do that, cover the carboy neck and slosh it around for a couple minutes. Not only will that aerate your wort (which you need to provide oxygen for the yeast to do their thing), but you'll also catch some of the yeast slurry that gets caught on the inside wall of the carboy. Don't worry if you miss a little bit, as the yeast will start reproducing on their own once fermentation begins.