I search fake cum like the one the slimewave site use.
Where buying this

Gaviscon.

Check out Violet Vixen here on UMD. She has a recipe that rivals the real jizz.

Oh sounds like you had a great time

I'm unfortunately not an expert on this, but it is something I love too. There are a lot of ways to make something similar so a lot depends on what you want to do with it. If you want to eat it vs use it vaginally or anally.

From what I've seen a methylcellulose concoction (usually a main ingredient in gunge) uncolored will have a very cum/semen like consistency if you make it particularly thick.

Similarly, J-Lube used frequently in Japanese lotion play videos also seem to work nicely.

Externally, either of those should be fine. But you'll want to do some additional research if you want to use internally.

Very easy to make, we make our own. Two things is all you need, Corn Starch and Water. Start off with about a gallon or so of water in a large pan on the stove, slowly heat the water , but do not boil, add the Corn Starch a little at a time and stir as you go , it will thicken as it warms up, adjust starch and temp to get desired results. Here is how ours looks.

I've played with a few fake cum recipes; the simplest being a white and uncoloured gunge.

From what I've noticed- my cum has two distinct fluid types in it- an opaque white fluid and a more stringy translucent fluid. (or I need to see a doctor!!)
By using two different types of gunge I was able to get very close;
MS gunge (extra thick - white) for the first component. 10L pack mixed with about 8L of warm water.
MS VIVI Extreme (uncoloured) for the second part; (which in itself is a 2 stage mix; A and B)
Mix 'part A' into about 8L of water.
Then drop in handfuls of the thick white MS gunge and mix with hand to break it into small suspended lumps.
Finally add in 'part B' (the activator) a little at a time. About 1/2 to 2/3 of the activator should get you somewhere near cum like stringyness.

Save the remaining activator for later; using the full activator gives a super stringy-stretchy gunge thats just crazy fun to play with in its own right. It can even siphon itself out of a jug!!

Dunno if i did it right but ywars, ago i bought xantham gum from the healty food store and thge resultant gunging was definitely rather cummy

Xantham gum with shaving cream