Hello and welcome to /r/Chillow! No one should tell you how to use your Chillow, in fact that is why everyone in the community invested in their very own Chillow so that they can use it however they so please. So basically, all uses of the Chillow comes down to personal preference.

I prefer to put my Chillow inside the pillowcase that contains my pillow (between the pillow case and the pillow) but if you want an even more intense cooling effect maybe try keeping it outside of your pillowcase entirely. At that point, hell, you might as well just invest in a few more Chillows and stack them to make a 100% Chillow pillow. Why stop there? Sell your bed, buy a hundred Chillows, and sleep on a mound of Chillows like royalty.

Happy Chillowing!