The audience paid to get Padma Lakshmi off the stage at The Moth’s storytelling event at Cooper Union Tuesday night. A spy said the “Top Chef” star was so “grating” as a host that a guest in the front row stood up and pledged to give the non-profit Moth $1,000 if she left — and she agreed. “She was rambling,” our source said. She told a long story about wanting to try a hot dog and later begged guests to donate $20 each. The man stood up and said, “I will donate $1,000 if you get off the stage right now.” Lakshmi’s rep said, “She was not intoxicated but having fun in an unscripted format … The person offered $1,000 and Padma said she’ll take that offer.” The Moth’s Catherine Burns added, “Padma curated and hosted a wonderful evening that the audience overwhelmingly loved … we were extremely moved by her generosity.”