hum diddy do dum dum

I have a friend who invented a gender neutral pronoun:  hum.  A combo of him and her? she and he?  Instead of saying 'she does not drink green tea', someone could make a gender-neutral statement by saing 'Hum does not drink green tea'. Does this work?  I like hum but I am not sure if it fits for him, her, she and he. And what about 'his and hers'. Could I write hum's? for the possessive pronounces his and hers?

Hum. What do you think.