justice jas no boner although big d did make concept art of what he looks like under the mask
If the Dead One is really Eldritch God like Hastur or Azathoth then it doesn’t matter to him in principle what the form he has because he can easily change it at will. I will even say more that then the Dead One can easily take away any person's body and use it as his own if he wants to. So... he can has a boner even in the form of a dead if he manipulates his body well... in certain places=)
BTW - Yes, in different Lovecraft books the concept of SHE and HE is mentioned but actually the eldritch gods can be and female and male or even both because It still depends on what form they use when they are living in the mortal world. So... i think the Dead One can be a ♥cute Dead One-chan♥ or just a very scary undead dude or something else... but it still depends on what Eccma himself meant therefore cannot be 100% accurate info but only guess based on Lovecraft books.
Anyway... It would be interesting even to see how the Dead One would look if he temporarily borrowed Lona's body.