Just a week or so ago, I was introduced to the Japanese site - http://www.akiba-web.com/ and while the majority of what it offers does nothing or me, I did come across something which caught my interest. Specifically, this video - http://www.akiba-web.com/product/index.php?product_id=3465 which features the use of an incredibly sticky slime substance.
It's the type of substance that I've been looking for for quite some time and already have several custom shoot ideas that would benefit from it's inclusion but I can't seem to work out exactly what it is. I'm curious as to whether anyone else has seen or even used anything similar and/or knows what it is made from and how to produce or otherwise get hold of some.
This has a very similar consistency to what you see on that Akiba-Web movie. It's relatively easy to clean up, but it's not actually sticky, but actually rather slippery.
2.) PVA Slime
It's all the rage nowadays. Just take some clear glue and detergent (or all kinds of other possible ingredients) and it can cause a good sticky effect. It's sticky, but not overwhelming, and AFAIK it's not as difficult to cleanup afterwards.
3.) Gummy Worms and/or Marshmallow
A lot of folks here have used this because it's cheap and effective, and can be cleaned up with some soap and water. Plus, it's got some real hold to it. The only bummer is you have to heat it up, and if you're not careful, it can cause some serious burns. It doesn't have to get super hot to melt into stickiness, though. Probably around 120F degrees or so.
4.) Rat Trap Glue
This is the ultimate stuff: You can buy gallon cans of this stuff, which is meant for putting into trays for glue traps. But if you have enough of it, it can trap people, too. As amazingly sticky as this is, you'll probably have a lot of trouble finding an actress who will handle it because it can really tear out hair, requires a LOT of cleanup (I'm talking hours if you get as much on your body as that girl in Akiba) and if you're renting a place, I wouldn't expect a damage deposit back from the landlord unless you're really careful. Plus, it's really expensive. I think a gallon can costs $20-30, whereas most of the slime and gummy stuff is probably around $5 per gallon overall.
Here's a few studios who have made some sticky movies, too:
Good luck finding a commission. I've found that most are fine with simple foot stucks, but if you are like me and love to see their whole bodies squirming and struggling in it, that'll be a tall order, in my experience.
Love you, too
) 
