The after-party for “Saturday Night Live” early yesterday morning at Primehouse glittered with host Elton John‘s colorful friends. “SNL” alum Steve Martin jumped on a banquette to roast the host in song, a spy said. John quickly jumped up to join him in front of guests including John’s partner, David Furnish, Lorne Michaels and most of the “SNL” cast. Earlier, John gave an extra performance for the live audience on-set, rocking the house with “The Bitch Is Back.” This was the first time John has ever hosted “SNL” and only his second time as the musical guest. He took on both roles this time. His first stint on the show was back in 1982. John, a new dad, also said it was “one of the best weeks of my life. “I’d like to say that with all the costume changes I didn’t get my penis caught in a zipper once. Maybe next time.”