You know, I used to think it was necessary to restrict an elf's access to her own pussy, and permission to masturbate. But as a human elf owner, married to a human husband, I've had plenty of time to observe our elf girl, and I've come to think that this might not be fair.
After all, my human husband is always involuntarily teasing her just by walking around in front of her, and her knowing that she can't have him whenever she wants, the way that I can. And surely she can smell it whenever he's even the slightest bit aroused, from clear across the house, whereas my senses are not keen enough to be alerted to his sexual needs all the time, the way an elf can. So clearly, she's quite taxed with the burden of being such an excellent source of sexual release for us both, that we don't use to her fullest extent all the time. Sometimes I have sex with my husband and his big human cock without even having her present, and she has to sit in the other room and fruitlessly grind her belted pussy against a pillow while she thinks about what we're doing. I mean, I assume.
So I think you should allow your elf to masturbate vigorously, it's the only way that they'll let off all that steam. You don't even have to allow her one of our artificial penis inventions that vibrate with caged lightning. She'd be perfectly happy with her own fingers. I would even say to let them out of their chastity belt sometimes, when no one is even having sex with her, in case your husband brushes up against her suggestively and she feels the urgent need to rub her pussy.
And you really should have her there as an active participant whenever you have sex. It might sound radical, but I would even say let her have first dibs on your husband, allow her to have vaginal sex with him, and take his first, fullest load of semen, instead of the usual sloppy seconds and anal sex we tend to allow our elves. A happy elf is a productive elf, and letting her be penetrated by your husband on a regular basis won't spoil her, like I used to tell her all the time while I flaunted my unbelted pussy in front of her and made her lick my pussy to get ready for my husband while she had to go without.