@yoshiii From my encyclopedia about symbolism, the bee is in China used in tales as guide with the purpose of revealing the good wife, also the term "bee" in chinese "feng" is close to an another "feng" which is the social ascension. Other probable symbolism is the lust of the youngs, there are also the symbolism in occident but it's almost all the time linked to christan culture so I don't think it's relevant.
The last one is the symbolism of bees in dreams, where it should be the representation of souls, so if it goes elsewhere you die, if it goes inside you or someone else, it lives.
My conclusion is that Tatsu and the old man felt alive for the first time in these moments, or he just fucked up the honey dosage.