This is also a line from the traditional British poem Cold, Haily, Windy Night, which deals with a similar scenario. The soldier begs a young lady to let him take shelter from the elements, and she breaks down under repeated pressure and "she opened and she let him in." Then she takes him into her bed and "she opened and she let him in." She blesses this night, and says "Soldier, soldier stay with me / Soldier, soldier won't you marry me?" But he bolts and leaves her to weep over her lost maidenhead.

The poem was made into a song by Steeleye Span on the album Please to See the King. It's on the more traditional end of their characteristic Celtic boogie style.