Police arrested a 22-year-old for selling concert-ready nitrous oxide outside a Disco Biscuits show at Irving Plaza last Friday. Carlos Holguin was picked up on Irving Place, where he had his nitrous tank and his pitch: “Four for $20.” The district attorney charged Holguin with unlicensed vending and unlawful use of nitrous oxide for intoxication. The Disco Biscuits were not charged for that awful name.