Fourteen-time Olympic gold medalist Michael Phelps, just back from his record-setting performances in Beijing, offered a prodigious high-five to a youngster in the McBurney YMCA pool on W. 14th St. last Thursday. The most decorated gold medalist in history, Phelps came to promote the YMCA’s “Play Every Day” program, then splashed around with some second graders from the pool’s swim program. Asked what he looked forward to most upon his return home, he said his dog, adding, “I miss the little guy.”