2.) Also refers to the act of proposing to a girlfriend prior to a long deployment, in attempt to make her feel obligated to him. This especially refers to instances where the couple is mismatched.
L:Hey, did you hear that Jen is pregnant?
C:Yea, Midshipman Quincy totally applied the Navy boxlock.
L: That sucks cuz she totally deserves better.
L: Midshipman Quincy just asked Jen to marry him dude.
C: Damn, I can't believe he wasted the Navy boxlock on her slutty ass.
L: Well, he was thinkin she'll stay faithful if he did that, but we all know she's been banging Nick behind her back anyway.