I found Jello brand white chocolate pudding has the perfect slightly off-white tone to match mayonnaise. I filled an empty mayonnaise jar with it and started eating from it with a spoon while some friends were over. The trick to really selling it was buying a pressure sensitive cap liner to reseal the top so I had to peel it open like a fresh bottle.
The reactions were 100% worth the trouble.
Whoa there, this is a children’s birthday party, not a bachelorette party.