The results are quite good but the foam needs stabilising or it goes watery. Superpants suggests glycerine, but I made a small amount of clear methyl cellulose slime and whisked that in - the result is a thick foam that's ideal for pies.
It's quite a bit cheaper than shaving foam, has more weight for throwing and since it's unscented doesn't sting the eyes.
I tested it out on myself quite vigorously this afternoon and was very pleased with the results.