That’s amazing. Thank you for sharing.
It's not a conventional retail experience, but I've been to ABU in Everett
many times. (I live in the area.) The place is, first and foremost, a warehouse. It looks pretty dumpy on the outside! You have to ring a doorbell and ask to be admitted, which is a bit awkward the first time. You might wonder whether you're the victim of some practical joke. I've never had a bad experience though. Everybody's been very welcoming, and there's a cute little retail space inside. There's also a fitting room with baby decor and an adult-sized changing table, which of course I had to try out.
When I went there to buy my first onesie, the employees helped me with sizing and gave me a free sample diaper (of whatever type I wanted) to wear while trying on the onesies. Before you leave, they quickly pack your in-store purchases into a plain box, just as if you'd ordered online.
Because it's a small place, and because you do have to interact with employees to get in, it might not be the best first ABDL store experience for somebody who's really shy. And it probably goes without saying, but they only sell ABU products. I wouldn't say shopping in person at ABU is worth a multi-hour drive, but if you're in the area...