A man to whom one is related by virtue of having had a slice of the same pie
. Bird's Second Law of Custardation states that six degrees of custard kinship would unite virtually the whole mammalian population of Earth. Most of them by way of a certain bitch-whore I used to work with.
Justin Timberlake, Kevin Federline, that Brummagem Paki, the Dave Clark Five, the fourth 'Lassie' and half the population of Detroit are custard cousins.
Two or more people who have had sex with the same person.
We both squirted our custard into her. Now we are custard cousins.