well yeah, as with fungus in general "he" is a bit on the odd and not easily classified side. but if you're strictly hetero, only searching for *female* domination, then you still have an issue here. no hate on anyone, but i personally don't wanna see anyone but the MC having a dick in the stuff i fap to, be it a regular guy, a "normal" futa with all attention placed on its oversized cock, or a mushroom monster possesing a corpse and creating some sort of ovipositor. in my male (strictly hetero) mindset all of those feel wrong.
gonna agree with ss6: if you do it, then please make it optional (and create alternatives/toggles).