Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 54, § 82

Before leaving the marking compartment the voter shall fold his ballot, without displaying the marks thereon, as it was folded when received by him, and shall keep it so folded until he has voted. A voter shall mark and deposit his ballot without undue delay, shall leave the space enclosed by the guard rail as soon as he has voted, and shall not remain within the guard rail more than ten minutes. No voter shall occupy a voting compartment more than five minutes, if all the marking compartments are in use and other voters are waiting to occupy the same, nor shall he occupy a marking compartment occupied by another, except as provided in section seventy-nine.