The snag with most liquids is that they leak through too fast to be useful. It also helps to wear several pairs as you can fill up the inner-most layers only (and they feel fantastic as they slide and rub over each other.)
Here's some suggestions I wrote on the subject a few years back, based on years of experience of tights sploshing with sloppy clay:
I'd suggest darker colours/black due to the use of light clay (good contrast). Use about 3 or 4 pairs. My faves were Brin Poudre from Le Bourget but they stopped making them a few years ago. Next were WoMan by Levee but they went bust! (I've heard that Stockings HQ are selling the 'magic' range which may be the Levee under a new name but not tried them yet.) A more recent alternative that I've tried are the 'Class' range from Levante. These are gorgeous, being both quite sheer (12 denier) and very glossy, as well as being relatively economical. There's something about the way the material is made that 'clings' to your thighs and all round the panty section and the way they slide over each other, which feels fantastic. Being only 12 denier, a couple of pairs of those next to the skin followed by a pair of Levante's Soft Opaques (thicker to help prevent leakthrough) over those then perhaps another pair of the glossy Class ones on top to make your legs shine and you'll look fantastic as well as being set up for some great wamming. (These are all still available from UK-based on-line shops such as MyTights.com) (Primark have some remarkably cheap but nice ones that are worth trying too and the 'large' is good for long legs, like the Levante ... but don't go for extra large if you need the length since, similarly to most, they're for wider rather than taller fit.)
Go to your nearest artists' modelling shop and buy a 12.5Kg sack of Modelling clay (type 1150) by Potclays (though you can get mail order:
http://www.potclays.co.uk/OrderProduct_ ... d=71654916 ). I see they also do powdered raw clay more cheaply (
http://www.potclays.co.uk/OrderProduct_ ... d=71654916 ) but I've not tried that so don't know what it's like. You'd also need a mask while mixing the powdered type as clay dust is NOT good for the lungs! It should be easier/quicker from powder though. (I usually get about 10 sessions out of a sack, but I’m very economical with it! Still, that's pretty good value for money anyway at £13 per sack!)
You now need to mix the clay. I would suggest breaking off fist-sized lumps and filling about half a bucket. Then cover these with water and leave for 24 hours. (You *can* do it on the spot but it’s hard work – pre-soaking makes it much easier to mix!) Next day, you can use something like an old wallpaper scraper to cut through the lumps and start to mix the clay with your hands or with a drill-mounted paint mixer. I also use a ½ pint measuring jug for pouring purposes. You need to mix it thoroughly to get rid of the lumps and the viscosity should be so that you can just about pour it, with uneven plopping, back into the bucket, which should just about level out without leaving peaks, but only just! (i.e. about the viscosity of barely mobile emulsion paint). Actually, that’s the advantage of clay – you can mix it to ANY viscosity and it doesn’t separate out (unlike mud) but stays creamy smooth and, at the recommended viscosity, it has coverage as effective as paint but without any chemicals against your skin, no horrid smell and a dead-easy clean up!
Anyway, put on your 3-4 pairs of tights and then put your panties over the top. (This is because you get a much nicer feel when the messy tights are against your skin and so that you can fill your panties (pref. High leg) and still see them as the glop dribbles out and down your thighs. Incidentally, tights aficionados all agree that they should be worn against the skin (normally without panties at all, of course) as they feel SO much nicer.) My own personal preference would be to add a stretchy-tight shiny lycra top plus a clingy knee-length stretchy lycra skirt (preferably without a split) on stand by. First, you might want to use some a little thicker (squidgy) clay if you want to plop some into your tights and drop your skirt down again so that you can walk around for a bit like there's nothing going on that's out of the ordinary - that always feels great - so naughty - your own little secret!
Now for the fun – it works better if you pre-wet the clothes with the shower head so that they don’t suck all the moisture out of the clay. (This will also please wetlook fans.) Then you can make some lovely handprints on your tits and arse using the clay and you can slip the skirt off and repeat the effect directly on the panties.
What I then like to do is to pour in some clay to the next-to-innermost layer of the tights (front and back) and feel it oozing round in there. (You don’t need much as it’s so dense.) Bending over, squatting down or sitting starts to feel really nice. Next, pour some into the innermost layer against your skin. Then repeat the bending and squatting. The great thing about clay with tights (if you've not thinned it too much) is that you can prance around at this point without fear of spillage but you can feel it all moving around and between your legs as you walk – fantastic! You can squish it from the back to the front, between your legs, which feels amazing! (You will not believe the wonderful squelchy sounds too!) You will probably find after a few minutes that it’s starting to work its way through. You could carry on filling up the outer layers of the tights, if you like, or cut to pouring some into the panties. Again – not a lot needed; the high density will drag your panties off with the high mass if you put too much in there (now there’s an idea !).
Alternatively, before you fill the panties, you can make ‘clay pies’ by pouring some clay on to a paper plate and splatting these on to you and sitting on them. The clay causes the paper plate to stick beautifully, which you can then peel off, but any semi-liquid clay runs straight down your legs, which is nice too.
Now that you are reasonably covered, you could slip back into the skirt and lie back with your legs in the air, then pour the bucket of clay into the bottom of the skirt (front and back) as if it and you were a big bowl or container. Then hold the bottom hem tightly round your legs and stand up. All the clay inside then slurps to the bottom of the skirt. Then you let go and it all gushes out and cascades down your legs which feels lovely.
When you’ve finished having fun, all you do is use a (blunt!) paint scraper to scrape the surplus off and back into the bucket. You can also put your hand down into the tights and scoop out any surplus (which is fun but even better is someone else’s hand!). It’s important to recover as much as possible as you don’t want it blocking the drains - an accumulation of it will set like concrete when dry! Strip off one layer at a time and (wetting it slightly again if required), pull the item through your clasped finger & thumb (like an old fashioned mangle), straining it to squeeze as much as possible out into the bucket. Then all you have to do is chuck them in the washer on the rinse cycle about 5-6 times and they come out perfect again! Likewise, a quick shower dissolves any clay on you and the place is clean again – so much easier than paint, mud etc.
Another advantage is that the clay is re-usable and maintains its viscosity for days on end. One tip is that, if you’re going to re-use it, you might want to put a few drops of bleach into it when mixing, to stop it going ‘off’, which has happened to me once in hot weather. (You'll really know about that if it does it - the smell makes you retch!) Bear in mind the bleaching effect on the clothes and your skin, however!
Have fun! I look forward to seeing the results!