Those that brag about doing those during their checkrides and training are almost certainly talking about doing them in Bell 2 bladed helicopters where it becomes a fairly simple and easy manuver . . . . . lots of intertia, even in the 407 that has lower intertia it's not so complicated, but . . . . in an R22 I'm sure it's a whole different story, that rotor will to zero in a nanosecond!