This (edible) fake cum recipe is pretty good and it’s a great way of really surprising your man!
Half a cup of water; 1 tablespoon of corn starch, 2 tablespoons of sour cream, one or two egg whites, and a tiny inch of salt.
Simmer the water and add the cornflour. Mix well - you don’t want lumps! Stir and add cornflour until you get a lovely gelatinous consistency. The next bit is really important. Let the mixture cool properly before adding the egg white (if you don’t, the egg white will solidify). Don’t mix it too much - you need to keep that sticky mucous effect! Add just a little sour cream (or natural yoghurt) for effect. And a tiny bit of salt - easy to overdo this, so go easy!
Pour the mixture into a glass, put a condom over the glass, and empty the cum into the condom. Remove condom. Put it onto a dildo. Blindfold your man. Have him suck the dildo and when you are ready, just make a small snip in the end of the condom. The cum will ooze out quite freely and he will wonder where the hell the cum is from!
Good instructional clip on how to make fake cum is here...
https://www.youtube.com/watch?v=n9y7AT-Uf20