Kuchikami-sake means sake that is produced through the process of chewing grain, such as rice, or seed in the mouth, spitting it out and leaving it as it is.
口噛み酒（くちかみさけ）は、米などの穀物や種実類などを口に入れて噛み、それを吐き出して溜めたものを放置して造る酒のこと。