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A man who has an ongoing sexual liaison with a married woman at her behest. An especially desirable arrangement for men who want the perks of a girlfriend without the worry of long term commitment.
Feel neglected? Never petted? Sister, you need to get yourself a boy in a box!

Oh Vic, sure Iā€™d leave my husband and breed with him, but he only wants to be my boy in a box.
by gildedprincess August 07, 2007
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