I have never shipped adult art, but I've had some shipped to me. They came in standard envelopes the same way photos would be shipped. All had a piece or two of rigid card stock to stiffen the envelope and "Do Not Bend" on both sides. One was in a plastic sheet protector with a blank sheet covering the art.

Good to know. I was kind of debating between either that or poster tubes. Not sure which would be cheaper/easier to ship.

ECMajor auctions off hard copies of his work every now and then. You could reach out to him about it.

Not a bad idea, thanks.

Dirty has a bunch of experience shipping things he may have answers to assist too

Ah, yeah. Good call!