@DjAlexDubCheck Ace is a common short form for "asexual". Asexuality, in case you don't know, is defined as "the lack of sexual attraction to others, or low or absent interest in or desire for sexual activity." by Wikipedia. This doesn't mean that they can't have sex or masturbate, they just aren't drawn to other people based on sexual attraction.
Your gays, straights, bis, pans and what have yous can be grouped together as "allosexual", meaning that they do feel sexual attraction to others and do have interest in sexual activity. They don't want it all the time, of course, but sex and anything related to it are very important to them.
And then there are demi(sexuals). They are "ace until proven guilty" to quote a meme from the sub-reddit and in between allos and aces. Meaning that there has to be a significant emotional bond for them to actually want to do it with their partner(s). "But isn't that normal?" Well, yes, but not for allos (who are more or less limited by society's standards). Demis really don't feel sexual attraction or desire towards a person unless there's a bond to them. It does not exclude any other orientations or attractions, so it's basically just a "modifier". The asterisks I used for aces still apply tho. Because sexual attraction, desire and physical reaction really don't have to line up all the time.
I call Edo demi because all of the sexual desire he might have shown has been around Yumika, the person he has the strongest emotional bond towards. Outside of family, ofc, but incest usually is not an option, no matter the attractions. Not mentioning that they have traumatized him...
Feel free to research more about these terms, as I have barely scratched the surface. But one last thing: The key to having sex with an ace (or demi) person is to give up. Don't pressure them. Otherwise they might feel that they have to give consent to maintain the relationship, which just taints it. (Cue me asking Yumika to be patient.)