What is the best technology to 3D print sextoys? Most 3D printing technologies create a rough surface. It cannot even be polished without leaving porosities. This is anti-hygienic. The surface has then to be coated with silicone or epoxy gel. The difficulty is to find a reliable inner skin contact safe coating.

Stereolitography create a way softer surface. However I find the materials to be too fragile for a sextoy use. Another point is that I'm not sure that it is safe for inner skin contact.

I know that CLIP can use PU. This is a more reliable material. I'm quite insure about the inner skin contact part too.

One can make silicone molds. This seems to be quite safe but also quite time consuming.

What can you say about it ?
I work for a company that doesn't make sex toys, but we do make silicone products with electronics inside, so I've seen lots of the same issues you're facing here.

The way we do it is to 3D print a mould for the object using an SLA printer (in our case a Form 2) - as you note, this material is rather brittle so doesn't work as the internal structure, but it's OK for a mould as it can be made as thick as required for strength.

We then 3D print the internals using an FDM printer in PLA or ABS (we use an Atom 2) and then cast the silicone around this using the SLA-printed mould. This is much stronger and you really have to work to destroy even the fairly delicate electronics once they're encased in silicone. As for contact with the skin, I've not checked the properties of any of these materials for safety in the body, but I would suggest that there's a reason people make sex toys in silicone.

To address your concerns about time, yes this is time consuming for the first one you make, but if you're making more than a couple the time saved by not having to print the entire object each time will more than outweigh the time spend moulding.