I see some Asian videos using a huge amount of what they call lotion - a clear (or sometimes white) very gooey and stringy slime. Often the video shows an entire bathtub filled with this, and I assume it must be somewhat affordable over there.

My question is this: Does anyone know how or where to order it, and if there is a North American equivalent substance?

Bath Slime by Rends or nuru powder from amazon will get what you need, though mixing varies in terms of output...and given that japanese baths are smaller than western ones, bath slime may need two bottles for a single tub. Nuru powder is much smaller batch and closer to what's in the videos. Both available online for the US

I have had success with a product called 'Yuck' - available in the USA, but it takes FOREVER to rinse off. A little goes a long way, but to make the stringy gooey mess, you need to mix it with less water. As a long-chain polymer, salt or using an abrasive wash cloth will help to break it down, but I was hoping the other products would dissolve easier.

Thanks for the suggestions, and I will be sure to try them.

Yeah, I'm definitely curious about the best practices for disposal?

J-lube

https://j-lube.net/shop?olsPage=products&sortOption=descend_by_popularity

I tried that but found it doesn't go very far. It would be crazily expensive to make a large quantity of the sticky, slimy clear stuff.