Slang for a Puerto Rican. Used because they often go for the $2 box cutter rather than a more expensive butterfly or switchblade. I was told this by a Puerto Rican himself, so I assume its legit.
A pair of pants, shorts, or any other article of clothing covering the "box" that is too small or tight and is shoved so far in her vag it looks like her box was cut.
Did you see Brittany's jeans? They're so tight on her fat ass they're box cutters!!
And dying in yo' bed many years from now, would ya be willing ta trade all da days from dis here day ta dat fo' one chance, just one chance, ta come back here as young men an' tell our enemies dat dey may take our lives but dey will never take our freedom ... YUB NUB!