Ejiao
Ar Jiao (Simplified Chinese: 阿胶; Traditional Chinese: 阿膠; pinyin: ē jiāo) is a traditional kind of glue from China, made from donkey hide. It is used in traditional Chinese medicine, and is also well known as the substance used for applying di mo, a special paper-like musical reed membrane, to the dizi, a transverse Chinese flute.
Ar Jiao is quite well suited to the task of applying di mo, since it dries quickly, holds quite firmly, and is water soluble, allowing later replacement of di mo.
If Ar Jiao is not available, a substitute can be improvised by simply crushing garlic into a fine, relatively dry paste, and applying as normal. It should be used quickly.