How do I cover my toilet seat?

Wow! Love to see this awesome toilet seat! Can you post a photo? If it is stained, you can take it off and strip or sand it down then re stain and reseal. But the toilet may be out of use for a few days.

Rustoleum 2X spray paint would work. Scuff up the surface to get rid of any shine with a green kitchen scrubby.

Sew a cover

Take the seat to the paint department of the home improvement store and ask them to select paint/stains and other finishes and application tools that will work. They have the best selection, the most up-to-date materials and most important, the most informative sales staff to get you what you need for a professional job.

how would I sew a cover?

Is it the seat or the lid?

What sort of material is it? I would even recommend spray painting it so it can dry quicker and won't leave you without a toilet.

it is the seat, but I should probably do the lid too so it matches. I was thinking of painting it...with a design...or just a wild abstract...would oil paint work?

Is it the seat or the Lid? You could use a Stain Blocker and then paint it. You could use a Dark wood stain if it is already stained wood. The seat top could be covered with an elasticated cover. (try Stool cover) some toilet mat sets also have a seat cove included.

Sand it down so a new finish will stick to it, do both the seat and the lid. If you'd like to fancy up the lid, take a look at Iron Orchid transfers:

https://ironorchiddesigns.com/iod-transfers/summer-2022-iod-transfers/

You might be able to use a paint that's made for porcelain or acrylic. There are epoxy kits.