Safety: what to put in a toy, what to leave out, and when to call a doctor
Short answer: use a non-porous material, give anything for anal use a flared base, use water-based lube with silicone, wash before every use, and get medical help for a toy you cannot remove. A 3D-printed plastic part is not a body-safe toy. This is why the tool makes a mould and casts silicone instead.
This page is not medical advice. It reports what health sources say and where they stop. Nobody we read certifies a home-cast toy as safe inside a body. For adults (18+).
Materials
WebMD, medically reviewed, names silicone, Pyrex glass and stainless steel as good choices because they are non-porous and can be sanitised. It warns against porous rubber, vinyl, nylon and leather, and says plastic or acrylic may leach chemicals. [WebMD] Porous means the surface holds bacteria that washing does not remove. That is the case against jelly and vinyl toys, and it is why the silicone page asks for platinum cure.
Nothing we read says a silicone you cast at home is body-safe. See what the labels certify. The maker of the toy carries the risk.
Why not print the toy
We found no source that says an FDM-printed plastic part is safe in a body. What we can say: the layers of a print show on whatever it touches, and a case study found the ridges carry into a cast. [Sinterit] A ridged surface is harder to wash, and the filament is not sold as body-safe. That is our reasoning, not a finding. The tool prints the mould and never the toy; keep it that way.
Flared base
Anything for anal use needs a flared base. Without one, the body can draw the toy in beyond reach. [WebMD] Planned Parenthood Toronto asks for the same list: smooth, unbreakable, flexible, clean, comfortable in size, and with a flared base so it can be gripped and removed. [PPT] Do not put an object that was not made for it in your body. The designer flags a base that is too small when the anal tag is on.
Lube
Use plenty. The anus makes none of its own. [PPT] With silicone, choose water-based. Silicone lube can wear the surface and leave microscopic damage where bacteria live. [Healthline] One maker says silicone lube does not harm platinum silicone, and the health sources say avoid it. We follow the health sources.
Washing
Wash with soap and warm water and air dry; silicone without a motor can be boiled for up to three minutes. [Healthline] Sources disagree on the boiling time (WebMD says up to ten minutes), so we use the shorter. A toy that touched the anus must not go into the vagina unwashed, or without a fresh condom. [PPT] Boiling and washing advice is for finished toys. We found no source for a home cast, so do a full wash before first use. See clean and store.
If something is stuck
WebMD reports nearly 39,000 emergency-room visits in the United States between 2012 and 2021 to remove an object from the rectum, and says to seek emergency care without embarrassment. It also lists constant bleeding, or pain together with bleeding, as reasons to see a doctor. [WebMD] Do not try to dig it out.
Sources
Read on 2026-09-20. Health: WebMD (medically reviewed), Healthline (medically reviewed), Planned Parenthood Toronto. Case study: Sinterit. The full list is in docs/GUIDE-SOURCES.md, section 9. We did not open a page on phthalates or on resin printing, so this page says nothing about them.