A substance I have rarely seen is Liquid Latex. You put it on as a liquid like paint, then it dries into a latex suit that can be stretched and peeled off. MessyFun did a video with it way back when, but I have not seen it much since.
Something that I use often and have not seen used by producers is drywall compound. You can pick up a 5 gallon bucket for about $10, bring it home and add a little extra water if you like, and you have more than enough white mud to cover yourself and a partner. You can even mix in some paint to color if you wish. I know there may be health risks from inhalation, but as long as it is kept moist that is of little concern, and any dry clay carries similar risks.
Thick black treacle, applied directly to the face in large quantities. You need a bowlful really, 4 or 5 litres of it, as it pours too slowly from a tin to give proper coverage. It's super thick, super sticky and completely opaque so it gives total coverage. However, it washes off almost instantly with hot water. It really is the ultimate wam substance, but it can be expensive and takes forever to pour it from the little tins into a big bowl!
Here's some pics from Splosh who do the best treacle pours in the business, and one from my own attempts to copy them!
Kustardking said: Thick black treacle, applied directly to the face in large quantities.
Agreed! 4 tins of black treacle was one of the 26 messes in Heather's A-Z of Mess video... but a few more litres would be great.
Also tried a few "treacle pies" with Bubbles (video coming soon), and will do more treacle work with the new girls that will be joining us later this month. The thick, opaque, slow-moving, engulfing qualities look great on camera!
Eggs, Honey, Maple syrup, and Oil! And lots of it. I think girls have a fear it will mess up their hair or something. But I'd love to see girls roll around and play in each of those (individually or all mixed, who cares).
Gotta keep the clothes on and have to get it in the hair first though and get them thoroughly soaked...then they can always come off. ;)